96 Lumina cruise control stopped working

Cruise control stopped working this month. There seemed to be a "warning shot" (some "surging" going down my rough road several times several different days). "Service engine soon" light has been on for months. Wife noticed 15 amp cruise control fuse was blown/replaced/blew again. I don't know and can't find where to look for cruise control module, troubleshooting, etc. I do miss the cruise and am a little short of $ for taking it to the dealer. Also I'm wondering if cruise control module (if the problem) HAS to be bought from dealer.

Thanks for any help on this

Check the wiring harness to the cruise module, as it could be corroded. I work at a Delco distributor and can get you the Cruise module way cheaper than the dealer will sell it to you.

The module itself is under the hood. It should be on the driver's side, bolted to the strut tower. If it blew the fuse right after you put it in, I'm guessing an internal short, or, like Richtazz said, something in the harness.

Thanks! Won't have time to check those out 'til Mon nite, then get back to you. I really appreciate your (both) advice (and parts offer).

I removed the plug from the cruise module/mechanical cable unit - no visible corrosion. I installed a new fuse, checking with cable unplugged, car on, car running, trying cruise - fuse didn't blow this time, but cruise doesn't work. (I didn't go very fast or far on the road trying it)

I copied down the number on the AC Delco part:AR 25161588A. It looks expensive. It looks like the mechanical cable part just unsnaps. If that's the problem (the module) it looks easy to change.

One more tidbit, check the stalk wiring at the knee bolster (under the dash, under the column) for proper switch operation. You may need something kin to a Haynes/Chilton manual to guide you in ID'ing the right wires, but a good check would just be see if you have proper switch operations (set, resume/acc, off). Last resort would be a bad brake switch, but that'd probably keep your brakelights on during driving, so it'd be easy to test.

Good tip Cad, didn't even think of the switch, duh! IF you need the module, the new GM number is 25344189, and I could sell it to you for $189.99 + shipping ($5-$10 usually for UPS ground). Dealer rade price is $262.15, and dealer retail is $374.50, just for reference.

I pulled the jack out on the turn signal arm and back-probed the contacts with straight pins - the "on off" and "set" switches seem to be working.

I found the wiring diagram and the colors seem to be right.

The switch at the brake was confusing. From my Chilton's it seems the brown/brown wires should only be hot/hot when the brake is pushed to disable the cruise. I seemed to get "light" on both sides of the switch in both positions. I couldn't figure how to get the thing out (more than once for all). I tried disconnecting the jack and the cruise still wouldn't work.

As for the connection under the knee bolster, I haven't got the momentum up to check it. I am beginning to think this is over my head, yet wonder if I'm close and don't know it (yeah, right).

I was hoping to find something simple. It'd be a real bummer to get the expensive part (thanks for the offer by the way) and it still not work, or, worse yet - blow the new thing with the still hidden problem.

Any suggestions?

If all the wiring under the dash up and to the firewall checks out, then it just may be the cruise module itself. Some internal motor winding could have melted its plastic insulator and is touching case ground, killing the entire system. Beyond wire checks and whatnot, I'm not sure what to suggest in terms of diagnosing the module itself. It may just be a bum thing. The surging may have been the motor failing, and it finally failed for good causing a short to ground.

Your Lumina problem sounds kind of similar to my 1994 Buick Regal. In my case the cruise control just quit working - no warning. The cc module in your Lumina is identical to mine, but the associated circuits look a little different - per Chilton's wiring diagrams. I checked most signals to the cc module - brake cut-off, multi-function lever and power/ground and all looked good. Had a repair shop look at it and they said it was the module. Found a new module at AutoPartsGiant.com and also at GMPartsDirect.com for about $200 (non-returnable). But -- that did not fix the problem. Took it the Buick dealer and they also said it was the module - I put in another new module - still no fix! Now what?? (I am now out $200 for a module plus a couple hours of labor charges for apparently bad diagnosis.)
I have not been able to find any info on the signals from the main engine control module (3 wires) to the cc module. I think one of them is from the Vehicle Speed Sensor (VSS) but if that is bad it seems like other performance issues would be evident. One other switch is called Cruise Control Cut-Off - anyone know what/where that is?
I would recommend checking all the switches before spending $$ for a new module.

I'm pretty sure the Cruise Control Cutoff is the signal the PCM gives the module when the transmission is shifted to neutral, or the brake applied. You may be getting a short to ground on the cutoff wire, causing the cruise module to continuously stay off.

I know everyone is talking about wiring ...but a vacuum leak will give similar symptoms...ck your hoses...!

I might probably be wrong but there doesn't seem to be any vacuum involved in this system. It seems to all be electrical/mechanical (cable)

Can someone tell me what that brake (cruise cutoff) switch is supposed to do? Is it supposed to connect or disconnect power when brake is pushed?

There's no vacuum in the cruise system, and the switch's signal simply tells the module to release its death grip on the throttle plate. The speed info is reserved until you turn the car off or turn off cruise, so no, power is not cut from the module itself.

there is often more than once switch on the brake pedal....

There are two brake switches - the top one has the right color according to my 20$ manual (brown/brown). The bottom has two jackfulls plugged in and I think (hope) it is all tail lights, back window light. (I un jacked the top one and wife said brake lts still flashed).

I thought I was getting test light (I was) on both the brown going in and the brown coming out with brake petal in either position. Can I assume this switch is bad? (I tried to use the cruise with this disconnected and it still didn't work.)

I got a positive fix for my particular CC problem.
The Reverse/Neutral Safety Switch mount on the transaxle was the problem. This affected four 'problems' - cc, door locks, backup lights and trunk release.
The cruise control module had been wrongly diagnosed because the scan of data from the main ECM indicated that the cc was enabled when it really was disabled - that could be a problem in the ECM but with no other symptoms becomes a non-problem now.
lectron44 - from the sound of everything you have checked and the fact that you experienced some surging, it points more and more to the module itself. I now have a used module (ACD 25140216) that you can probably talk me out of for a pretty cheap price.

johndmc,

Thanks for the offer. My neighbor is visiting his friend's junkyard in Peoria this week and thinks he can get the module and brake switch - it may not work that way.

If it doesn't work out what do you need for it, and is it the same as mine? (different number than was posted on this thread)