hey guys i need your infinite knowledge. Ive tried everything i can think of to get my cruise control working again to no avail. I have a late 99 with a 6 speed. so far i have checked all the fuses with a multimeter, ive checked continuity from the harness under the dash through the clockspring to the switches, truck doesnt start without the clutch pushed in so the neutral safety switch works, has the upgraded switch and harness off the master cylinder. the previous owner said the cruise was intermittant about a year after they did the harness and switch recall on it. is there a way to test the harness and switch? any help would be greatly appreciated, i got a 1800 mile round trip coming up in about a week and im gonna have a sore foot if i cant figure this out.

 

forgot to add that horn doesnt work on the steering wheel however it does work when using the key fob to lock the truck. no airbag lights or any of the sort. Thanks guys.

 

I'm not an expert on the 99, but know the 97 well. Check the brake lights for proper bulb operation including the third one in high rear of cab. Also make sure they are not LED types as it confuses the PCM on current draw thinking you are braking all the time.

Hope Ford took care of this issue in the 99, but don't really know. In any case I'll bump you up top for some experts to help.

 

The only thing I can add is the horn and cruise use the same relay on my e99. I removed the relay since the horn would blow randomly, and now no CC. Hope that helps some.

 

That points to a problem with the clockspring under the steering wheel. If it were the relay the horn wouldn't work with the fob.

 

I have the same problem with my 99 F350 SD. I had the intermittent trouble with my CC before the recall. Horn works fine. Now my CC does not work at all. One thing I did notice was when the CC would work, if there was a small bump in the road, it would disengage. I tried holding up in the break peddle thinking maybe it was tied to that but it didn't resolve the issue. I am at a loss.

 

Echoing what mark said, my daughters 500 had a sad taillight bulb fixture and the car thought the brakes were applied at each bump cancelling it.

Easy diag is to pull a taillight bulb in sequence till it stops doing it and go after the predator.

Denny

 

Thanks for the help guys. Ill dig into the brakes a little bit more. i wonder if there is a pin at the pcm that i can read resistance or continuity through to tell me if anything is messed up in that circuit. I dont think its a clockspring issue otherwise i wouldnt have had continuity through the clockspring i would think it would read infinite or out of limits. Thanks again!

 

Just because starter works with clutch engaged does not mean clutch switch is OK.

The switch can totally work in one direction and not the other. Just went through this on my personal truck.

Remove switch and and inspect it.

 

You can check all of the switches (and consequently clock spring) with scan tool.

 

well i pulled the clutch safety switch and everything looks good there, thanks for the idea. like i said i checked continuity through the clockspring and everything seemed solid. checked the harness that was changed during the recall and it has good continuity through it so none of the fuses are blown. the brake lights appear to be operating correctly... however i noticed i dont have any backup lights... not sure if that would affect it or not. so basically im left with brake pedal position switch, brake safety switch, or i dont even know...

 

The scan tool will tell you if the clutch switch is sending signal to PCM.

Clutch switch has 2 positions - engaged and disengaged. Recently, my cruise stopped working. I went through a lot to figure out the clutch switch was only working on the engaged side (so starter worked). My temporary workaround was to remove switch from clutch pedal and manually manipulate it so I could start truck, then slide the switch to disengaged so I had cruise control while driving.