Cruise, Horn, Miss, Shudder

[CADY9641]

Hey all you tech savvy GM people. My motive in joining the forum is completely selfish, but perhaps it will help some other unfortunate soul in the future. Just maybe, I'll become a rock star contributing member some day. Who knows.

For now I'm looking for some advice. I recently purchased a low mile 99 Yukon out of Kentucky. It's in great shape but needed a little sprucing inside. By the way, anyone that tells you essence of ash tray is easy to remedy they are not, I repeat not your friend. In fact they probably have some new fandango eco-friendly car deoderizer they want to sell you. Enough of that, on to the issues...

First, my cruise works when ever it pleases. On again, off again. No consistent behavior pattern. The only thing that seems to occur regularly is, when the cruise is working and you hit a decent bump it shuts off. I suspect that's something to do with a brake sensor but not necessarily the overall cause for intermitten service.

Second, the horn. Oooh the horn. Again with the intermitten stuff. The horn itself is good. When I pull the relay I've got proper voltage and when I short it out the horn blows. I figure it's between the horn switch in the steering wheel and the convenience center in the engine compartment. Oh, and yes the fuse and relay are good.

Next on my list is an engine miss. I started noticing it at freeway speeds and only when fuel is getting low. Come to think of it, I noticed it when I test drove it as well. That was between 30-40 mph mostly. It was also low on fuel for the test drive. By low I mean quarter tank or less in both instances.

Finally, a shudder at moderate to high speed. It's something that's more heard than felt. Like a dull, low growl that resonates inside the car. I've heard it before. It would show up when a u-joint was failing in a GM cargo van I used to drive. Then again I also heard a similar noise in my 97 Nissan Maxima when a wheel bearing went bad. Things to note on this issue; tires have been balanced, two different shops say the u-joints and wheel bearings seem ok. Not sure how you qualify that without taking things apart but I'm led to believe they can.

Anyone with a reply that leads to a fix gets a 100 Grand. Nestle that is.

P.S. Are there any GM mechanics that contribute to this forum?

 

[tspain]

Okay, first thing with your horn and cruise. It sounds like they may be related. Your multifunction switch (turn signal switch), has the horn contact and cruise switch made into it. It may be the cause, but diag. without having the vehicle in front of me is hard to do (electrical wise)

Second, your miss. It sounds like you have a fuel pump starting to go out. You need to install a fuel pressure guage on the fuel rail and check the pressure as you drive and when it's acting up. See what the fuel pressure is. It should hover around 60psi.

Lastly, your shudder noise. Is this truck 2 or 4wd? It could still very well be a hub bearing, or u-joint. They don't have to "look" broken to be broken. The bearings in the hub could be failing causing noise, also the u-joint could be worn and still causing noise. It could also be caused by a rear end noise, or if it's 4wd, it could be a front diff noise. As above, kinda hard to diagnose without driving it myself.

Let me know if you need anymore help and I'll do my best to walk you through it!

Welcome to the forum!!

 

[CADY9641]

Hi Thomas. Thanks for the post.

So the horn has some sort of electrical connection to the blinker/cruise stalk? Interesting. I've made a few discoveries since my original post that may help things along.

Regarding the horn, I've discovered that if I give the steering wheel a spin or two the horn will generally start working again. The cruise remains a mystery. However if what you're saying is true and they both share a similar power source and or ground in the multi-function switch that could make sense. If that were the case though I would think they would either be working or inoperational at the same time. Either way, I suppose it couldn't hurt to replace the multi-function switch. It's not too expensive and it would eliminate a possibilty.

New info on the "miss". It's actually not a miss at all. What I was interpreting as a miss was actually originating from transmission activity. It's an erratic and frequent downshift from lockout to OD. Not sure if I've properly stated the activity. I don't have a very broad repotoire of mechanic speak. From what I understand you've got four drive gears and lockout. That gives you four shifting points; 1-2, 2-3, 3-OD, then there's that final "shift" that drops the rpm's a few grand more. I think I've heard that referred to as lockout. Anyway, that's what I keep feeling.

Lastly, the shudder. It's 4WD and I agree with your assessment. Unfortunately I lack the experience and expertise to be able to identify which piece is causing the noise without servicing each in a process of elimination. I may be better off taking it to a shop for that.

Your input is appreciated. If you've got additional thoughts regarding the above comments, please post. Thanks again.

 

[tspain]

With the details of the horn problem, it sounds like there is a buildup of grease on the horn terminal. Its kinda hard to expain it.

Behind the steering wheel there is a plastic piece that has a metal ring on it. Your multifunction switch (turn signal switch) has a little metal tab that rubs on this ring. The factoy puts grease on this ring and sometimes there is too much and it interups the contact. Cleaning off the excess grease will fix it.

Now I'm not 100% sure that's the problem but it's worth checking out. But it could still be the switch, due to the wacky cruise.

On the miss, it sounds like torque converter shudder. The "lockout" your refering to is called torque converter lockup. I would get your transmission serviced with a flush, not just dropping the pan and replacing the filter. You need to get all the old tranny fluid out, plus most flushing systems have an additive that helps reduce the shudder of the apply.

Lastly on the shudder, I would take it to a reputable shop, possibly a dealer. I know I know, evil dealer. They aren't all bad and they aren't all out to get your money. We have the special tools, know-how, and resources to fix some of the most craziest things that can happen to vehicles.

Take it to a shop and have them help diag. it.