1989 gmc s15 cruise control

Printed From: the12volt.com
Forum Name: Cruise Controls
Forum Discription: Cruise Control Settings, Tach Signal, VSS PPM(Vehicle Speed Signal Pulses Per Mile), Vacuum, Brake, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=5683
Printed Date: May 05, 2025 at 3:24 PM

Topic: 1989 gmc s15 cruise control

Posted By: philly
Subject: 1989 gmc s15 cruise control
Date Posted: November 20, 2002 at 9:12 AM

I have a gmc s15 89' and the cruise control works but only up to 95 kmh after that it shuts off. I've checked the vac. lines. if I try to engauge it at higher speeds it does nothing. it does not even try to turn on but if I slow down to 95 kmh or less it works fine. Any Ideas?

Replies:

Posted By: PLAYER69
Date Posted: November 20, 2002 at 5:27 PM

strange! check to make sure your throttle linkage is adjusted correctly. It could be maxing out and the servo can't pull the the throttle any more to hold the speed at a hight speed.

If you set the cruise at say... 110km/h and let off the throtle, when your speed reaches 95 will it then pull the throttle and hold at 95?

It could also be a faulty servo under the hood that pulls on the throttle. Check out this website for getting a remanufactured unit www.rathwellhardware.com

Posted By: philly
Date Posted: November 21, 2002 at 6:49 AM

no if I'm above 95 and set cruise and let off the gas nothing happens unless I set it again at 95 I'm lost, I think I'm just going to get a used complete system from the scrap yard and try that.

Posted By: anonymous
Date Posted: November 21, 2002 at 6:07 PM

Depending on where you bought from I've seen a couple of units purchased in the States that wouldn't engage over 55 mph.

Posted By: philly
Date Posted: November 25, 2002 at 11:44 AM

it's a factory unit I got out of a scrap yard. It was out of a 4.3 L Jimmy and I put it in a 4.3 L s15 pickup. Is there a way to trick the cruse control into thinking I'm going slower. My digital dash is broken so my speed display isn't working, It doesn't matter if I change anything.

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