Common problems

[Captain D]

I have had 3 Broncos 95XL, which I sold and own a 95 EB and a 96XLT. All three have had the same two problems.

(1)-Step on acceletor or put the engine under a little load and the dash vents close and ac comes out the defrost vents.

I know it is a vacuum leak and have been able to fix for a short period of time, but it comes back. Just an annoying issue.

(2)Tailgate window switches-I have spent way too much time trying to diagnose and fix.Have followed steps recommended here,but can't fix or am unwilling to do more to the new Bronco I have. Jumped motor wires and it goes up and down easily.

Can I just wire the motor to a toggle switch that has reverse polarity and momentary on/off? Is 20 amp capacity enough or go with 30 amp capacity one?

Input would be greatly appreciated.

 

[Rons beast]

The vaccuum issue I have had too....after I completely replaced every inch of the plastic vac line it has been fine.

Yeah the window issues are a pain. Aftermarket window switches are available, and I think a 20 amp would be good. I would use relays and not run full amperage through the switch anyway.

Good Luck let us know how it turns out.

 

[Seabronc]

Where do you propose putting this switch? If it is the dash, then you will need to run your own set of wires back to the motor. If you use the old wires, then you will find that it probably won't work for the same reason the existing one doesn't work. I have in effect done the same thing but used the existing switches and ran heavier wire from the front to the back, #10 ga. The tail gate harness is already #10 ga, but the existing wires going from front to back are #12 ga. In the process I eliminated the troublesome old connectors which are the cause of most of the problems.

Good luck,

 

[Captain D]

I am going to run all new wiring to a toggle switch to the dash. I am bypassing all the stock stuff.

 

[nelbur]

I know from experience that the tailgate window problems can be frustrating, but once you find the problem and fix it, you would be happier than if you jury rig something. Before you give up, unwrap the wire loom where it goes between the tailgate and the quarter panel. On my Bronco the flexing and twisting there actually broke one of the wires. Once I fixed it the window has worked fine for several years. I believe Ford will still sell you all of the switches. The problem is that the circuit is a bit complicated because of the two switches involved. There are only two switches, and a safety switch on the latch, so if your wires are good, replacing the switches might be easier than jury rigging it.

 

[Seabronc]

I agree with nelbur that it is better to trouble shoot the problem. I don't agree that the circuit is complex, the only thing here is that the wires running from front to back are loaded with failure points, but with some patience and a volt meter it is a fairly easy circuit to trouble shoot. The main failure points are the connectors, where the wire is flexed, and the latch safety switch. I upgraded my wires to eliminate most of those locations and increased the size of the wire to reduce the voltage drop to the motor. One thing you need to keep in mind is that the wires going to the dash switch have dual function and that they are the ground return path for the motor. So any problem in the path prevents the motor from functioning. Also there are two voltage sources, one for the dash switch and one for the tail gate key switch. If both switches fail to function, it is most likely the latch switch, or the ground return path. However I have seen cases where the connector to the motor was the problem, but this is probably the rarest case.

Diagram attached

 

[Captain D]

I agree with nelbur that it is better to trouble shoot the problem. I don't agree that the circuit is complex, the only thing here is that the wires running from front to back are loaded with failure points, but with some patience and a volt meter it is a fairly easy circuit to trouble shoot. The main failure points are the connectors, where the wire is flexed, and the latch safety switch. I upgraded my wires to eliminate most of those locations and increased the size of the wire to reduce the voltage drop to the motor. One thing you need to keep in mind is that the wires going to the dash switch have dual function and that they are the ground return path for the motor. So any problem in the path prevents the motor from functioning. Also there are two voltage sources, one for the dash switch and one for the tail gate key switch. If both switches fail to function, it is most likely the latch switch, or the ground return path. However I have seen cases where the connector to the motor was the problem, but this is probably the rarest case.

Diagram attached

You both are right. I get frustrated and want to take the easy way out sometimes.I don't have time to do the proper job at the moment. You have inspired me to do the fix the right way and I will when I return from this out of town job.

Thanks for the good advice.

 

[miesk5]

yo,

On the vacuum/Defrost/AC

The air handling system is designed to provide defrost when no vacuum is applied to any of the three air door vacuum motors. This is done to prevent a situation where defrost cannot be obtained due to a system vacuum leak. Instead, a leak in the vacuum control circuit will send all airflow to the defroster outlets. This condition may occur during acceleration (slow leak), may exist at all times (large leak) and may happen only when certain specific functions are selected, indicating a leak in that portion of the circuit. ..." from F-150, F-250, F-350, F-Super Duty and Bronco, F-Super Duty Motorhome Chassis Workshop Manual

Source: by Ford

"...The vacuum hoses used in the passenger compartment control circuit are constructed from PVC plastic material. The vacuum hoses used in the engine compartment are constructed of Hytrel. Because of the materials used, the vacuum hoses should never be pinched off during diagnosis to locate a leak. Use Rotunda Vacuum Tester 014-R1054 or equivalent to locate vacuum leaks. A wood golf tee can be used as a plug when it is necessary to plug one end of a vacuum hose for leak test purposes..." from F-150, F-250, F-350, F-Super Duty and Bronco, F-Super Duty Motorhome Chassis Workshop Manual

Source: by Ford

Check the Control Valve's vacuum line for damage

Vacuum Control Valve Depiction in 92-96

http://info.rockauto.com/Motorcraft/YH486.jpg

Location near pass. side hood hinge/firewall

http://i23.photobucket.com/albums/b390/bwolfe84/DSC00801.jpg

by Bob W

Vacuum Leak Test; On an idling engine check for vacuum leaks using a mechanic's stethoscope with the probe removed, or a ~3' garden hose section. Don't spray flammables on a running engine. MIESK5 NOTE; Also check: vacuum hoses; intake manifold gasket & throttle body; PCV line; vacuum reservoirs: EGR Sys Vacuum Tank & 2ndry air (coffee can); AC, heater, defroster, vent control ckt & vacuum tank (plastic ball type), under dash & lines to heat/blend/etc. doors; power brake booster; cruise control ckt, etc.... where applicable; (combined w/ Steve83's info, thnx) BEWARE OF BELTS/PULLEYS, FAN AND HOT ENGINE

Source: by miesk5 & Steve83 at Ford Bronco Zone Forums

If vac line needs repair;

This is Ford's method:

Vacuum Line/Hose, Mini-Tube Service in Climate Control System in a 96; "...Measure the length of the damaged area of the mini-tube vacuum hose. Cut a piece of standard 3mm (1/8-inch) ID vacuum hose approximately 25mm (1 inch) longer than the damaged area of the mini-tube vacuum hose. Cut the mini-tube vacuum hose on each side of the damaged area and remove damaged portion of the mini-tube vacuum hose. Dip the mini-tube hose ends in Tetra Hydro Furan (THF) or Methyl Ethyl Ketone (MEK). Either of these solvents will act as a sealer for the repair of the mini-tube vacuum hose. Insert the ends of the mini-tube vacuum hose approximately 9mm (3/8 inch) into the ends of the standard 3 mm (1/8-inch) ID replacement vacuum hose. Shake the service joint after assembly to make sure solvent is dispersed and vacuum line is not blocked internally. Test system for a vacuum leak in area serviced..." from 1996 F-150, F-250, F-350, F-Super Duty and Bronco, F-Super Duty Motorhome Chassis Workshop Manual

or

Vacuum Line (Hose), Mini-Tube Damage Repair in a 92 Source: by JohnMcD348

or;

Vacuum Hose (Line) Replacement w/Rubber Hose in an 89 F 150 5.0; "...This should cover most 87-96 V8s (302\351); for the I6s (300)s the solenoids are in the same general area, as well as the valves. You can use this article as a basis to replace yours, just keep in mind it..." Source: by Booba5185 (Matt)

or Get Vac hose at NAPA, etc. and replace.

If you want it look good,

Vacuum Line (Hose), Silicone in Red, Green, Yellow, Silver/Gray, Purple, Black, Blue in 1/8" to 1" I.D.; hiperformancestore.com; NOTE, Never use silicone hose for fuel, oil, or any petroleum base products.

Source: by miesk5 at Ford Bronco Zone Forums

Vacuum Line Acronyms & Color Codes;

EMISSION: Red = Main vacuum;

Green = EGR function;

Orange = Heat control Valve (exhaust & intake) (AKA heat riser but more complex, im older vehicles);

Yellow = from the TAD Solenoid (driver's side Forward Solenoid) to the TAD (Diverter) Valve located at the rear of the Intake Manifold (Distributor Advance in Carbureted Engines);

White = EGR vacuum (source);

Black = Mainly used for the Evaporative emissions control;

Black = Thermactor ACV or Diverter valve; Blue = Throttle Kicker control; Pink = from the TAB Solenoid (driver's side rear solenoid) to the bottom of the Thermactor Air Bypass Valve (TAB or BPV/AIR Bypass (AIRB) valve);

ACV (Air Control Valve) is the TAD (Thermactor Air Diverter) Valve (AIR Bypass (AIRB) and AIR Diverter (AIRD) valve combinations);

MAN VAC is Manifold Vacuum;

FPR is Fuel Pressure Regulator;

EGR is Exhaust Gas Re-circulation Valve

SOL V: Thermactor Air Diverter (TAD) Solenoid (SOL V) (AIRD) & Thermactor Air Bypass (TAB) Solenoid;

EVR is EGR Vacuum Regulator;

VRESER is the Vacuum Reservoir Can (Tank);

V REST on later years is Vapor Valve (Roll-Over @ Gas tank);

V REST on earlier years such as 78/79 & SEABRONC's 83 is a Vacuum Restictor/Delay Valve, it restricts vacuum for a certain amount of time, on most engines a vacuum line from the carburetor base runs to a T & then to V REST to the distributor;

Carbon Can is Carbon Canister (Charcoal Canister, Vapor Canister, Evaporative Emission (EVAP) Canister);

MAP is Manifold Absolute Pressure Sensor;

AIR BPV is the AIR Bypass (AIRB) Valve, also called the TAB (Thermactor Air Bypass) Valve;

CPRV is Canister Purge Solenoid Valve/ Canister Purge Solenoid (CANP);

VCKV is Vacuum Check Valve;

CAT is catalytic converter;

ENG is engine;

PCV is Positive Crankcase Ventilation Valve.

HVAC in 92-96;

Black = from engine source to vacuum check valve & to vacuum reservoir tank & to Control Panel;

White = actuates the Outside/Recirc air door two-position vacuum control motor;

Blue = Mix (actuates the FLOOR/PANEL air door two-position vacuum control motor);

Red = Floor Flow & Y

ellow = Panel, (actuate the FLOOR/DEFROST three-position air vacuum control motor).Source: by Steve83 (Steve, That dirty old truck), Seabronc (Rosie, Fred W), Seattle FSB & miesk5 at Ford Bronco Zone Forums

Vacuum Line Acronyms & Color Codes;

EMISSION: Red = Main vacuum; Green = EGR function; Orange = Heat control Valve (exhaust & intake) (AKA heat riser but more complex); Yellow = from the TAD Solenoid (driver's side Forward Solenoid) to the TAD (Diverter) Valve located at the rear of the Intake Manifold (Distributor Advance in Carbureted Engines); White = EGR vacuum (source); Black = Mainly used for the Evaporative emissions control; Black = Thermactor ACV or Diverter valve; Blue = Throttle Kicker control; Pink = from the TAB Solenoid (driver's side rear solenoid) to the bottom of the Thermactor Air Bypass Valve (TAB or BPV/AIR Bypass (AIRB) valve); ACV (Air Control Valve) is the TAD (Thermactor Air Diverter) Valve (AIR Bypass (AIRB) and AIR Diverter (AIRD) valve combinations); MAN VAC is Manifold Vacuum; FPR is Fuel Pressure Regulator; EGR is Exhaust Gas Re-circulation Valve SOL V: Thermactor Air Diverter (TAD) Solenoid (SOL V) (AIRD) & Thermactor Air Bypass (TAB) Solenoid; ; EVR is EGR Vacuum Regulator; VRESER is the Vacuum Reservoir Can (Tank); V REST on later years is Vapor Valve (Roll-Over @ Gas tank); V REST on earlier years such as 78/79 & SEABRONC's 83 is a Vacuum Restictor/Delay Valve, it restricts vacuum for a certain amount of time, on most engines a vacuum line from the carburetor base runs to a T & then to V REST to the distributor; Carbon Can is Carbon Canister (Charcoal Canister, Vapor Canister, Evaporative Emission (EVAP) Canister); MAP is Manifold Absolute Pressure Sensor; AIR BPV is the AIR Bypass (AIRB) Valve, also called the TAB (Thermactor Air Bypass) Valve; CPRV is Canister Purge Solenoid Valve/ Canister Purge Solenoid (CANP); VCKV is Vacuum Check Valve; CAT is catalytic converter; ENG is engine; PCV is Positive Crankcase Ventilation Valve. HVAC in 92-96; Black = from engine source to vacuum check valve & to vacuum reservoir tank & to Control Panel; White = actuates the Outside/Recirc air door two-position vacuum control motor; Blue = Mix (actuates the FLOOR/PANEL air door two-position vacuum control motor); Red = Floor Flow & Yellow = Panel, (actuate the FLOOR/DEFROST three-position air vacuum control motor). READ MORE - I have compiled this info from the guys in various posts here in da Zone...Source: by Steve83 (Steve, That dirty old truck), Seabronc (Rosie, Fred W), Seattle FSB & miesk5 at Ford Bronco Zone Forums

OFF

In the OFF position, all doors are in the vacuum-applied position with the exception of the PANEL door. The blower & compressor clutch circuits are not energized.

MAX A/C

In the MAX A/C position, all vacuum operated doors are in the vacuum position. A/C damper inlet door (19C802) air is shut off and the passenger compartment air is recirculated to maximize cooling. Discharge is through panel register. A/C clutch & blower circuits are energized.

NORM A/C

In the NORM A/C position, outside air is allowed to enter the passenger compartment. The air passes through the A/C evaporator core (19860) and is cooled before reaching the passenger compartment. Discharge is through panel register. A/C clutch & blower circuits are energized.

VENT

Ventilation is delivered through the instrument panel registers when the function selector **** in the A/C control (19980) is set in the VENT position. In the VENT position, no vacuum is applied to the OUTSIDE/RECIRC. vacuum control motor (18A318 ) and the door is open to the outside. The air coming in through the cowl is discharged through the panel registers. The blower circuit is energized, but the A/C clutch is not.

FLOOR

In the FLOOR position, no vacuum is applied to the vacuum control motor and the OUTSIDE/RECIRC. door is open to the outside. Air is discharged through the heater outlet floor ducts (18C433) with a small amount going to the windshield defroster hose nozzles (18490). The blower circuit is energized, but the A/C clutch is not.

MIX

In the MIX position, outside air is discharged through the windshield defroster hose nozzles and the heater outlet floor ducts. A/C clutch & blower circuits are energized.

DEFROST

In the DEFROST position, outside air is discharged through the windshield defroster hose nozzles with a small amount going to the heater outlet floor ducts. All doors are in the no vacuum position. A/C clutch is engaged in ambient temperatures above approximately 10�C (50�F) & the blower circuit is energized.

The PANEL/FLOOR, FLOOR/DEFROST and OUTSIDE/RECIRC doors are vacuum operated.

For maximum cooling, the temperature **** should be set in its fully counterclockwise position; the function **** should be in the MAX A/C position; and the blower motor (18527) should be set for a desired rate of airflow.

Even though the function **** is on MAX A/C, the temperature ****, being manually controlled, may be set to modify the temperature of the air and the path through which the air flows. Another characteristic of the MAX A/C setting is the increased noise level of the blower motor. Speed does not change when the OUTSIDE/RECIRC. door is moved to either of its two positions. The difference in noise level is that an open recirculation door exposes the passenger compartment directly to the noise. When insulated against the noise with the recirculation passageway closed, the speed appears to be less.

The control **** operates an A/C switch that is attached to the backside of the A/C control by one ***** and retainer tabs.

Five hoses (black, white, red, blue, yellow) extend from the A/C control just below the electrical connector for the mode selector switch to the vacuum control motors and vacuum supply. The solid black hose goes to the vacuum supply through a tee-shaped A/C vacuum check valve (19A563), which attaches the A/C vacuum reservoir tank and bracket (19A566) and engine source. The white hose actuates the OUTSIDE/RECIRC. air door two-position vacuum control motor. The blue hose actuates the FLOOR/PANEL air door two-position vacuum control motor. The red and yellow hoses actuate the FLOOR/DEFROST three-position air vacuum control motor. Each end of each hose slides onto the ****** of the vacuum port to which it attaches.

Lastly, get the Vehicle Emission Control Information (VECI) Decal,

for 88 & UP.

On-Line for Free at Ford.

Click "Quick Guides" in left panel;

Scroll to & CLICK VECI Labels "Provides Vehicle Emission Control Information (VECI) and a related calibration parts list." Enter applicable info (need to know your Calibration number from your B-pillar sticker).

Vacuum Diagram is the same as the one on the core support or hood or air filter cover.

Source: by Ford http://www.motorcraftservice.com

 

[miesk5]

Yo,

TG Glass part...

Switch, Key By-Pass (Constant Power for the Tailgate Window); "...I'd like to share with you what I did for my rear window, and many of you folks may have already done something similar. I too was tired of having to have a key to always open the rear window. So, I schemed up a way to power the window at all times from the dash switch without having to splice a single factory wire. I have a dual battery system, and a 1-in/6-out auxilary fuse block behind the glove box, (I cut away a small portion of the back wall of the glove box to accomodate this). The auxilary fuse block, of course, runs off the auxilary battery, at least when the truck is off. So, I first took a fuse, (any old fuse) and blew it. I then put the blown fuse in the factory fuse block in the position for the rear window fuse. Now, the window is obviously not getting power from my main battery with a blown fuse. I then took one of those little power taps (these are little clips which are specifically made to clip around an ATO style fuse) and put it on the "dead" side of my blown fuse (i.e. the side which is not supplied from the ignition switch from the main battery). I then connected one end of a 12 guage wire to the fuse power tap with a female crimp on connector, and ran it across the dash over to my auxilary fuse block. I moved the original mini circuit breaker over to my auxilary fuse block to retain stock amperage protection. Whala! My rear window now works independent of the ignition switch, it draws from the auxilary battery when the car is off, and as an added bonus, my door windows are obviously on the same circuit as they now work all the time too. I have been using this setup for several months, on cold days when the window doesn't want to move and hot days, with no problems. I didn't have to splice a single wire, so should I need to return to stock, it would take under 3 minutes to reverse the above steps. Some of you have probably done something far more sophisticated than this, but I thought I was pretty clever for thinking this up, and that's not a feeling I have often..."

Source: by Keith L (TTB Blows, Bling-Bling) via Chris B (Blue, bronco boy) at telus.net

Switch, Key By-Pass; "...This assumes that your motor,and safety switch are good, this also allows you to rewire the switch to work without the ignition if you prefer. (1) run a fused wire from the hot side of the starter relay, 10 gauge or larger into the cab, if you want to bypass the ignition then cut the lite blue/black wire on the dash switch and tie into this hot. (2) Cut the pink/green and pink/blue wires on the switch. Connect two 18 gauge wires to the pk/grn and pk/blu, Run the two 18 gauge wires along with the 10 gauge hot wire behind the driverside kick pannel, under the door sill past the seat belt and behind trim panels until you get to the rear. (3) Remove the drivers side tail lite to access the tailgate plug in, drill a hole from behind the tail lite thru the inner quarter pannel. (4) Cut the pk/grn, pk/blu, and black/white wires, splice in three 10 gauge wire to these and route them inside. (5) Get 2 Bosch type 5 pole relays and wire them as follows.(one relay will control up the other down) the 10 gauge hot need to be wired to pole # 87 0n both relays and to the black/white wire tha goes to the TG. Poles number 87a and 86 0n both relays go to gound. The pk/grn goes to pole #30 on one, the pk/blu goes to pole #30 on the other. One of the two wires that you ran from the dash switch goes to pole #85 on one relay, the other goes to pole #85 on the other.( if the winow goes the wrong direction switch these wires) remember to make good connections and good grounds. this will take all of the load off of your dash switch and make the relays do all the work. you should be able to do all of this for under $50 ALSO make sure you get the right kind of 5 pin relay, if it doesn't have pole 87a then you have the wrong one! good luck and have fun!!..."

Source: by Dazed and Confused

For more TG Info LINKs, see my site @ http://www.broncolinks.com/index.php?index=478

Such as;

Wiring Diagram, Dash Switch Test, & All TG Connector Locations Diagram in 92-96 Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net