Cruise Control

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Skitter302

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First trip home in the Bronco I used cruise control and it seemed fine. Here it is about a month and a half later and during a 300 mile trip and the cruise control acted really wacky. Sometimes you could set the speed just fine other times it would set cruise at 80% acceleration. This problem only seems to happen if Cruise Control is set higher then 55mph.

Let me give you an even better idea of how wacky it can be.

Say you want to set the speed for 65mph. ON > SET ACCL (Bronco stays at set speed for 3-5seconds) :: Bronco then speeds up on its own(70,75+). Hit the OFF button and cruise turns off. Hit ON, Bronco resumes to accelerating on its own. OFF>OFF>OFF then ON>SET ACCL (Bronco Cruise Control proceeds to work.)

Sometimes you have to hit ON > SET ACCL (Bronco stays at set speed for 3-5seconds) :: Bronco then speeds up on its own. SET > SET > SET
(Bronco Cruise Control then accepts speed and will maintain it. But by the time you have the speed set you are now have the speed set for 70mph.

Another quirk is that after Cruise is set and speed is maintained. Using the Right Blinker will deactivate the Cruise Control just like hitting the OFF button or touching the Brakes. My right blinker also has the issue of not staying in place on its own. Feels like the plastic tab that holds the blinker on is busted off.

I'm putting this out here as a brain teaser and having said that, I don't expect any body here to be able to explain how to fix this but suggestions are sure welcome.

 
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I would start by replacing the turn signal switch in the steering column. This gives power to the wheel. While doing that make sure the round metal contact are clean on the actual wheel. A quick tip to replacing the switch is to take the connector off and tape the wires together and run them through the same spot. Just a place to start. Just a place to start at.

 
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Skitter302

Skitter302

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So your thinking that the problem might be more in the wheel then the Cruise module under the hood?

 

miesk5

96 Bronco 5.0
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Yo Skitter,

For now until I do some physical therapy;

Check vacuum with a gauge, should be around 15 to 22 in.

Cruise (Speed) Control (Vacuum) "TRICKS OF THE TRADE" Troubleshooting TSB 90-25-12 by Ford for 86-91 Bronco, Aerostar, Econoline, Explorer, F-150, F-250, F-350, Ranger & cars 
Source: by Ford


Intermittent or Inoperative Speed Control Operation May Occur During Wet Weather Operation TSB 92-7-8 for 86-91 Bronco, Econoline, F-150, F-250, F-350 & Ranger, 91 Explorer, 86-90 Bronco II; "...May be caused by a corroded connector at the servo; Inspect the connector at the servo for corrosion to determine if replacement is required. Refer to the following procedure for service details. Disconnect the connector at the servo Blow dry the connector assembly with shop air. Clean and inspect pins for corrosion Replace any damaged or corroded pins (D1AZ-14488-E). Apply grease (F2AZ-19584-A) to both ends the connector to prevent water entry..."

...

Turn Signal Replacement:

  • "Unscrew/remove the turn signal/tilt lever, pull the steering wheel (you may need a steering wheel puller) and remove the turn signal switch screws.
  • The turn signal switch harness is a very tight fit through the steering column to the connector under the dash, especially with the harness connector attached.
  • First, look closely at the new signal harness connector at the end of the new harness and write down the wire color locations. Ensure that the new connector is the same as the old one.
  • Locate the base of the signal harness connector under the dash by pulling on the top from the signal switch. Be sure that you locate the correct wires!!!
  • Then I just cut the wires on the old signal cam harness before the old connector and pulled it out from the top of the column.
  • Un-pin the wires from the new connector and tape/feed the wires back down through the column.
  • Re-pin the new connector, referencing the old one, and reconnect to the main harness.
  • Re-install the turn signal switch, steering wheel and turn signal lever and your done.
I highly recommend a new Ford Turn Signal Switch & Harness for longevity and especially "feel". (Aftermarket Turn Signal Switches break easily and feel "funny")." by SeattleFSB

...

Speed Control Wiring Diagrams in a 91 Bronco;

http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=11322

&

http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=11323 ( includes vacuum circuit from servo modulating valve to dump valve)

 
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Skitter302

Skitter302

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I would start by replacing the turn signal switch in the steering column.

I was its an easy starting point. But it could as well be the module under the hood.
Your Right! The issue is in the wheel. I'll have an expert change this part out for me.

 
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Summary of story: the cover where the buttons and horn are might be the issue and there is no fixing it since the only replacement is sitting in a junkyard likely with the same issue unless you can pull it apart and really reshape it or possibly add spacers. It might have collapsed over the years and it's a series of contact pads underneath that weren't that well designed in the late 80s/early 90s which are now being engaged to some frequency. The horn and cruise control all operate via a single wire from that pad into the steering wheel column so they operate over signaling, not just power i.e. one fails, then they all fall down (or do some weird shit).

The issue with my truck is the center steering wheel cover but my problem was much worse. The horn was constantly engaged and it all started while turning a corner in a Jack in the Box drive thru. Something tells me my food was spit in that night ;) /emoticons/[email protected] 2x" width="20" height="20" />
After ripping out a bunch of fuses just to get my food I finally got the right one and was able to move on.
So I removed the cover and everything was fine as it looked but the problem remained. I replaced the turn signal switch 4 times (new not junkyard so $90 a pop in my 20s........) and each time after 4 to 20 signal / turn wheel engagements where the signal will disengage after completing a turn, the lil clip on the bottom side broke so it's back to 100% manual signals still to this day. Seriously F' that switch and it's not exactly the most pleasant replacement job either.... Still replacing the switch never changed the horn or cruise control. Just temporarily fixed the automatic blinkers.

So I tear apart the wheel cover electronics because my cruise control also took a dump on me now too and I replaced all the vacuum lines for it.
The amazing part of the horn and cruise control is it's operated all through a single wire so it must use signal modulation at the ECU to figure out what function was engaged but that still doesn't explain the horn. I bet the engineers were VERY proud of this design and despite the crappy contact pads, I give them kudos for the era. I dunno, this was all baffling but the catch is, they're all connected together with that single wire so the potential for "wonkiness" is pretty high.

I tore apart the cover itself and found there are contact pads underneath which is expected. The issue is they are very poorly designed and with the age of the rubber and the heat of AZ, the cover has collapsed itself to the point that it creates constant contact on some of the areas especially the horn since that's a huge contact pad vs. the others being buttons. Since they're all connected though, and the horn is constantly in contact, there's no way for the signaling for the cruise control to occur since it is washed out with the signal of the horn since it all occurs over a single wire.
Now this was 10-12 years ago and I just gave up but I suppose I could 3d print or just add something as a spacer. I thought I did but I'm not trusting the decade old memory of me trying and, obviously failing if I did, to fix anything. So I'm done with most of my revamp of my Bronco (yes she's legal on the road again!) so maybe I'll just tear into that cover and try to fix that too. If I do and fix it I'm sure I'll make a post :) /emoticons/[email protected] 2x" width="20" height="20" />
 

 
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Skitter302

Skitter302

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I would start by replacing the turn signal switch in the steering column. This gives power to the wheel. While doing that make sure the round metal contact are clean on the actual wheel. A quick tip to replacing the switch is to take the connector off and tape the wires together and run them through the same spot. Just a place to start. Just a place to start at.


Just want'd to post an up-date on the progress of this issue. Had the turn signal switch replaced and the issue still is there. Mechanic diagnosed the issue to be the cruise servo. Was looking at O'reilly's web site to get a new one buy they don't seem to match my part. Do I need to reuse my own cable or do I need to find a servo with a cable?

 

miesk5

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Yo Skitter, 

I would replace cable if it's damaged.  

Following by Ford in 96 Workshop Manual;

"When performing visual inspection, check all items for abnormal conditions. Look for such items as bare, broken or disconnected wires. For the speed control to function properly, speed control actuator cable (9A825) (throttle actuator) and throttle linkage should operate freely and smoothly.


Actuator Cable


  1. Remove cable retaining clip from actuator cable at accelerator cable bracket (9723).
  1. Set throttle plate to closed position.
  1. Pull on the actuator cable to take up any slack. Back off at least one notch so that there is 1mm (0.040 inch) of slack in the cable. The cable must not be pulled tight for proper operation.
  1. While holding the cable, insert the retaining clip and snap securely
cruise-servo-93up.jpg

 
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