2nd Gen Non-Engine/Transmission cruise control wont stay where i set it

[BEiselstein]

I have been having a problem with the cruise on my 99 when i set it at around 55-60 it will continue to gain speed up to about 70-80 it will do this almost everytime i set it i have to hold the decel button and continue to for about 30 seconds to a minute before it will finally calm down my right foot gets a little heavy if i dont set it and im tried of fighting it

 

[AMink]

IIRC, there is a wire that runs by the driver's side battery. At least on my 97. It can wear through. This seems to be a pretty common issue. Mine didn't ever work right. Do a search on cruise control and you should come up with something.

 

[CCiatteo]

On my 97 I had the opposite problem. The cruise would slowly loose speed and it turned out to the vacuum pot under the driver side battery was rusted/eaten by battery acid. I replaced the vaccum pot ($60 from dealer) and everything works great. And its great to have cruise control back.

What year truck? The later trucks might have the cruise controlled through the ECM or something?

Chris

 

[BSMcCauley]

I had the same issue with my '96. Had to either set the cruise control about 20 mph below where I really wanted it (and then bump it back up with the resume/accel button), or hope I didn't get a blue light special in the 10-15 miles required for the factory unit to calm back down to set point. Lived with it this way for about a year. Then finally replaced the factory setup with an aftermarket cruise control from JC Whitney salvaged from another rig and I like this one much better. Have it set up to control down to 20 mph and it holds speed at +/-0. 25 mph within limits of engine power/braking. Also can hit "resume" once I get above 20 and it will pull the throttle open only as far as required to get the rate of acceleration programmed in -- which also happens to be about the way I normally accelerate manually. The factory unit would go to WOT in this situation and stay that way until overshooting the setpoint.

 

[CumminsPower98]

I once had a bad overshoot problem just as you describe and it turned out to be the servo. No acid problems either as I have optima batteries. When I took it apart it looked like one of the tiny components on the circuit board might have been bad. I paid only $32. 21 for a new unit from the dealer back in '06.

 

[radyvolk]

I had the same problem & this TSB 18-08-99 solved the problem. Now when I set the cruise it stays dead on to what I set.



Randy

 

[BSMcCauley]

... it turned out to be the servo. ... I paid only $32. 21 for a new unit from the dealer back in '06.

My dealer wanted around $90 for the new servo when I went in asking about it. Perhaps the parts guy wasn't looking at the correct part -- or might have been trying to sell me everything from the mounting bracket to the TPS...

 

[Joe Mc]

My vote is for the Cruise Servo - underneath left battery tray. Mine did the same thing as yours. I think it was back in 02 I replaced the servo, $70 from the dealer and it's been fine ever since.

 

[B.G. Smith]

I have been having a problem with the cruise on my 99 when i set it at around 55-60 it will continue to gain speed up to about 70-80 it will do this almost everytime i set it i have to hold the decel button and continue to for about 30 seconds to a minute before it will finally calm down my right foot gets a little heavy if i dont set it and im tried of fighting it

There was a problem with the 99 (I had one) and the solution to mine was to set the cruise when the truck was neither accelerating or decelerating on level stretch of road and let it run in cruise about a minute, repeat three times and it would level out. Hope this helps. bg

 

[CumminsPower98]

My dealer wanted around $90 for the new servo when I went in asking about it. Perhaps the parts guy wasn't looking at the correct part -- or might have been trying to sell me everything from the mounting bracket to the TPS...

I wasn't paying retail as I order all my parts through the company name at work so that might be part of the difference.