90 Bronco wiring help

So I'm new to working on trucks and recently bought a 1990 Eddie Bauer with a 351w and c6 transmission (both recently put in by previous owner) to learn.

Im having problems getting it started. I got it to fire up once by putting a screwdriver to the starter solenoid. I can't get anything from the ignition switch( that's all I've got (previous owner used it instead of the key) he had tried putting a remote start on the car and didn't finish it. I ripped it all out to try and get back to the basics.

I have a Chilton for the truck and have been trying to decode the wiring diagram for my truck (im completely lost) to try and make sure everything is where its supposed to be.

I've put in a new starter, changed all the fuses, and took out the wires crimped into the original ignition switch and recrimped the original wires. I stopped there in fear of messing it up anymore. I thought it may be the nss and found the wires from the old and I think the new transmission but they look mangled aaand covered in tranny fluid because he put the old transmission in the back which leaked fluid everywhere...

If anyone could guide me in the right direction and educate me along the way I'd be extremely grateful.

I'm including pics of the wiring, hopefully it doesn't give anyone as big of headache as it gave me! Thanks!

Hey AH,

The wire at the small post on the start solenoid (red with a light blue stripe) is the signal wire from the ignition switch. When that wire gets power the solenoid contacts close providing power from the battery to the starter.

I saw in your pics that wire was spliced close to the ignition switch. it also was in some pics showing it going to connectors that were not connected.

First verify that you have 12v+ coming into the ignition switch with the key off.  ( believe that is through the yellow wire, but not sure. My wiring diagrams are not available right now.)

Your wiring diagram will show what provides that power into the switch. Then you need to trace the red/wltblue stripe wire out to the solenoid, verifying that there is continuity from the switch to the solenoid.

Good Luck 

Yo,

Let'start with what I have and know is correct.

EDIT.... I DELETED A PIC OF THE STARTER RELAY AFTER FINDING THAT THE OWNER HAD INSTALLED A PMGR STARTER AND CHANGED STARTER RELAY WIRING.

Wiring Diagrams, same as by Ford:

http://www.revbase.com/BBBMOTOR/Wd

Are you having any issues reading the diagrams you have now?

Since previous owner rigged start ckt, I assume ignition key cylinder or switch or ignition actuator rod is defective.

No Start Troubleshooting; "...First thing to check is wiring. Between the large posts of your starter relay (it's not a solenoid) should be a smaller post with a wire attached. This is the wire from your ignition switch through the Park/Neutral Safety Switch (NSS)/Manual Lever Position Sensor (MLPS), Or clutch safety switch on a manual trans, or NSS/MLPS with an AOD/E4OD, to the starter relay and the on to the starter solenoid (if equipped) and starter. Check this wire for cracks, open insulation, or anything that could possibly cause an open circuit. Next, check your upper ignition actuator. Find the ignition actuator rod (on top of the column, running from the steering wheel down to the ignition switch at the base of the column) and make sure it's moving back and forth when you turn the key, through all positions. If it is, your upper actuator is probably not the problem. Lastly, check your ignition switch (again, at the base of the column). Manually push the switch back and forth through the different positions. Push it all the way forward (or down) and see if it will engage the starter. If it does, then your ignition rod is probably bent, which can be remedied quite easily. & If it's an auto, try starting in neutral or while pulling up on the lever while it's in park. If that works, look to the Park/NSS/MLPS. If it's a stick, check the clutch switch. You could try jumping from hot to the small terminal on the starter relay to test it's operation. Sometimes new ones are bad out of the box. If it won't turn over when jumped to the small terminal, you'll know that it's a starter relay issue (Bad part, bad ground or a bad starter. Check to see if da relay is tight to inner fender with no corrosion because the relay's body is ground path via inner fender). If it does turns over jumped to the small terminal, then you'll be looking for something in the small circuit that includes the ignition switch & the park/neutral safety switch (NSS/MLPS) Or clutch safety switch. There should be 12v running from the ignition switch, thru the NSS/MLPS, to the small terminal on the starter relay. Disconnect the small wire to the starter relay (So it doesn't start by surprise, I'd pull the coil wire too). With someone holding the key in the start position, you should be able to read 12v between any point on that small circuit & ground. When you find where you lose 12v, then you'll know where the issue is.

MIESK5 NOTE; from Ford EVTM; The Control Module (PCM) runs the pump{s} for one second when it receives an ignition- on signal. It also runs the pumps as long as it receives a PIP signal from the Hall-effect devices, it continues pump operation even after the key is released from START. If the PIP signals fall below 120RPM, the control module cuts off the signal to the fuel pump relay or the integrated relay control module. The pump will also run when the terminals of the fuel pump test connector are jumped. the Control module signals the pump when it receives a CRANK signal, and when the Control module gets PIP signals that the engine is running. the pump does not run if the PIP indicates the engine is not running even with ignition ON {except for that first one second}.

Source: by BigUgly88EB and ElKabong (Ken, El Kabong)

No Start Troubleshooting; "...If you can't start the Bronco from the key/cylinder it might be the "upper ignition actuator" has broken in it's track inside the steering wheel OR could be just the key cylinder itself which "pops out" if you look right under it on the metal column collar, there's a little slot and with the key turned to RUN -engine off push up inside with an appropriate tool and comes right out. You can either jump start the vehicle from the "starter relay" under the hood, right inside fender area or pull off the "black plastic cosmetic column shroud" exposing a long 'ROD" and with the key turned to RUN using a set of pliers, drive the ROD downward/forward and the vehicle will start with most key functions intact....i.e, RUN/NO START, OFF/LOCK, AUX..."

Source: by JKossarides ("The Bronco", Jean)

Ignition Switch Pin-Out Diagram & Continuity Testing in 87-91 (from Factory manual and the Factory EVTM guide (electrical, vacuum troubleshooting guide)

Source: by Broncobill78 (Dave) at Bronco Zone Forums

http://broncozone.com/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=6659

Thanks for the advice guys, I'll check today to see if the ignition switch is getting power and trace the ignition wire too. In the pic you posted, miesk, on the starter relay, is there a wire coming off the bottom terminal (I) part of the relay? I don't have that

Yo,

Sorry, just noticed that Seattle Bronco had switched to later year PMGR (Permanent Magnet Gear Reduction) starter.

So, NO there is no wire on that bottom center terminal, secured with a nut.

Here is Ken'so 1990 Bronco pic showing the inner fender mounted relay;



Here is another starter wiring diagram

http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=17413

OK cool, thanks for clarifying! Mine is setup close to the one in the picture except the ground to my starter is connected to my positive terminal on the battery and the smaller cable to the smaller terminal on my starter is on the left terminal on the starter relay.

So I tested the ignition wire to my ignition switch using a test light and its getting power. I was wondering if it could be my battery? I took one in to auto zone 2 days ago to have it tested and recharged because it seemed weak from jumping it too much. I left it there for a few hours and came back and it wouldn't charge so they gave me a new one( didn't have to use my warranty) the battery has 750 CCA. Is that enough?

AHBronco90 said:

OK cool, thanks for clarifying! Mine is setup close to the one in the picture except the ground to my starter is connected to my positive terminal on the battery and the smaller cable to the smaller terminal on my starter is on the left terminal on the starter relay.

Click to expand...

I hope that a ground is not attached to the positive on the battery, You better check out the connections and make sure you have them attached to the correct locations.

>-

Yo,

Battery should be For Southern States only CCA: 650

750 cca for all other states

Std Automotive Battery

according to Ford at:

http://www.fordparts.com/Commerce/PartDetail.aspx?n=KN6LYPDGYsMuwpaKzdAgaA%3d%3d&id=344399056&m=44&search=true&year=1990&make=Ford&model=Bronco

Now, read this:

Car Battery Review - Best Car Batteries - ConsumerSearch.com

http://www.consumersearch.com/car-batteries

"Walmart's EverStart MAXX-24F finishes just behind the top batteries in expert tests. ... The EverStart costs less, though, and -- unlike Sears -- Walmart installs car batteries for free. ... Cold-weather car batteries -- often labeled "North" or "N" -- have higher cold-cranking amps (CCA)."

And my battery review Posted 07 September 2007 - 03:18 PM

Walmart Everstart Maxx 65N; 850 CCA, 1000 CA (manufactured by Johnson Controls)

yo gang, I purchased this battery last week at WAL MART� (battery is not listed in their web site)

It is mfg. by Johnson Controls & produces this EXACT SAME battery (CCA, etc.) for many auto makers and retailers under different product names such as:

Motorcraft� silver BXT-65-850; ~$100.00 to $120.00 Plus $104.95 + tax, etc. at your local friendly Ford dealer

Sears Die Hard Gold 33065 $105. +

Auto Zone (Duralast Gold)

Eveready

Everstart

Interstate Mega-Tron Plus $104.95 + tax, etc.

Toyota (TrueStart)

Mitsubishi (Diamond Car Care)

Mazda

Advance Auto (Autocraft Titanium)

Costco (Kirkland Signature)

Pep Boys (ProStart & Energizer)

btw, Johnson also mfg. Optima brand

WAL MART - excellent price $61.00 w/ 7% sales tax and free installation. The warranty is 3yr free and 108 month pro-rata

CCA: 875 amps @ 0 degree F/ CA = 1090 amps @ 32� F; Reserve capacity: 165 mins

compare CCA etc to Optima YellowTop

CCA = 500 amps @ 0 degree F/ CA = 625 amps at 32� F; Reserve capacity: 70 minutes

Update, price is now (Feb 2016) $109.97

Hey Ah,

As  Seabronc said above. Remember the + power flows through the start relay when it is activated. The ground is provided by the attachment to the fender. There is no "ground" wire to the relay as it is just a heavy duty switch.  (+ power from the battery at all times on a heavy gauge connection in....+ power out to the starter through heavy gauge connection,  when it is activated by the ignition switch and wiring through the small gauge wire "red w/ ltblue" )

The connection from the battery + post will also have smaller gauge wires providing feeds from the alternator and to the main wiring harness.

The other heavy connection on the relay will be a lone heavy gauge cable down to the starter.

Good Luck 

Oh man I had a buddy tell me it was hooked up wrong and told me to put it there. I'll change it immediately. Thanks seabronc. And thanks miesk those are awesome prices compared to what I was looking at. I'll get mine tested and if its dine I'll pick up a new one and see how it goes. Thanks for the info Ron's beast, electrical is completely foreign to me and its best to learn the right way. I'll adjust and keep you all updates. Thanks again everyone!

So is this wrong? The thick wire( I used the wrong term, not ground) to the starter is hooked to the positive terminal on the battery and that smaller wire on the left post on the starter relay is hooked to the small terminal on the starter.

Ok...I think I'm getting an understanding of your wiring.

Let me review:

1- There is a heavy gauge wire running directly from your starter motor to the + terminal of your Battery...correct?

2- There is a smaller gauge wire running from the left heavy post of the relay on the fender to the starter, attached to a smaller terminal there...correct?

If so this is not factory wiring and not a standard factory starter set up.

This still can be made to work properly.

The smaller gauge wire is the starter activation wire. ( it closes the circuit to the starter motor and activates the solenoid to engage the gear. Like GM starters, as oppose to most Fords that have only the one heavy gauge wire .  The previous owner installed that starter and has attempted to activate it by using the factory relay on the fender as a source of + power to run the starter. (This is what the thinner gauge wire from the relay to starter is for)

To get that starter to turn and do it's job we have to "close the switch" that is the relay on the firewall. that is done by supplying power to the small post at the top. ( the one with the red wire w/ lt. blue stripe) 

Normally that wire is energized when the key is turned to the start position and then closes the circuit in the ignition switch. that provides + power to the relay on the firewall, first passing through the neutral safety switch.

Try this:  jump from the battery + to the small post on the relay on the fender. ( the one that has the redw/ ltblue stripe.) It's ok to pull that wire off for this test.

IMPORTANT!!!!    HAVE THE KEY TURNED OFF TO PREVENT THE ENGINE FROM STARTING. 

This is only a test for the starter and relay circuit.

Applying power to that small post should make the starter engage and the engine crank.

If it does you only need to find the reason the red/w lt blue stripe is not getting power when the key is turned to the start position.

This doesn't mean everything in the wiring is fine but you will have eliminated the starting circuit under the hood.  (It's a bit carved up but can work.)

Let us know how this turns out.

Good Luck

Hey so I did what you said and the engine started to crank (won't turn over)

Is there a way with the starter I have to make it more simple? Rewiring it to the ford factory way?

For clarity "cranking and "turning over" are referring to the same action of the starter turning the engine.

To return to the factory wiring you need to replace the starter with a stock  1 wire unit. As well as changing the cable to the starter from the +battery terminal to the left terminal of the solenoid. Discard the thinner wire to the starter...OR ​leaver the thinner wire and the starter as is.

Switch the cable from battery +  back to the left side of the relay ( thick cable and thinner wire both on the left post of the relay.) and proceed with the checks I listed below.

The wiring is done the way it is because the starter you have requires constant +12 Volts and the + power to the solenoid to engage.

Now try to turn the key to the run position and jump the start relay on the fender as you did before.

Caution...be sure the tranny is in park and everything is clear under the hood....you will be starting the engine. ( getting the engine to fire)

if the engine fires, or sputters as if it will start you know the circuits are good to provide the electrics for the engine to run...( thumbs up!)

The next thing is to check the circuit from the ignition switch to the relay on the fender.

Do you have +power out of the ignition switch in the red wire/wlt blue stripe when the key is in the start position?

​no= ignition switch miss adjusted...not activated by the rod from the key cylinder...or part is bad.  (all is assuming you have power into the switch)

yes= good check for power into the neutral safety switch (NSS)

no= bad connection to the NSS...run a new wire to the NSS

Yes= do you have power out of the NSS with the tranny in park?   In neutral?

no= NSS is misadjusted or part is bad

Yes= trace the wire out of the NSS to the relay on the firewall. ( sometimes it's easier to run a new wire).

Once that is done the engine will crank with the key in the start position just as it did when you jumped it.

Good luck

​Good Luck

Hey Rons beast, I followed your instructions and am now cranking from the ignition switch! Thanks! I'm now checking all the spark plugs to see if they're good. I'll keep you all updated

Yo AH,

Great!

Fyi, Spark Plug Inspection Chart

http://www.aa1car.com/library/reading_spark_plugs.jpg

Hey miesk, I checked all of them by resting each of them one at a time and cranking the engine yo look for a spark. They all did. Now I'm thinking it has to do with the fuel pump, fuel pump relay, or wiring to the pump. I listened for the hum when I turned the ignition on and heard nothing. Any advice?