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Intermittent Electrical Problem


New Member
Mar 11, 2003
Garland, Texas
I've had my Avalanche for almost 3 months and I love it, BUT, after this weekend, a reliability issue has reared its' ugly head.

Friday morning the truck would not start. The battery appeared to be fully charged because everything electrical worked normally, but nothing happened when you turned the key. A boost did not make any difference. The dealership came and got it and said it had a dead cell in the battery. They installed a new battery, and my son and I went on a little camping trip for the weekend. Sunday morning the AV would not start. Same problem. New Battery, plenty of juice to run everything electrical, but nothing happened when you turned the key. Another tow to another dealer, (60 miles from home). When this dealer's service guys looked at the truck on Monday, it started normally, and showed no stored codes or any problems of any kind. I've got the AV back home now, but still think I have a problem waiting to pounce at the worst possible moment. Anybody ever run into anything similar? I would appreciate all suggestions.

Sounds like it could be a bad starter solenoid to me. If it happens again, and you know where the starter solenoid is, try tapping it with a broom handle while someone holds the key to start. (Be very careful when doing this, serious injury could occur - standard disclaimer) Or if you have a mechanic friend that has a remote start button, it connects to the starter and bypasses the solenoid, you could try that.
There's a whole lot of things that could prevent starting your engine, from PassLock, to the PCM, etc. If there is a problem, most of those should store a fault code.

While it could turn out to be just about anything, the fact that there are no codes makes me think that it is either the starter solenoid mentioned above, the start contacts in the ingition switch, or the start circuit wiring.

Intermittant problems are the worst. If it fails while the diagnosis is going on, this shouldn't be a hard problem to find. But if it isn't happening when the testing is being done, this will be next to impossible to trace.

How frustrating. It must be so stressful getting in to start up your truck, wondering when will be the next time that it leaves you stranded.

-- SS
Hi 5string,

Have you installed any electrical items on the truck?
Poked around with a volt meter or test light looking for a hot wire etc.??

It is incredibly easy to create a loose connection if you stick a probe in any of the wire connectors. The GM service manual has a special warning about sticking test probes in connectors.

I was looking for an ignition hotwire on mine. Created an intermittent connection on one of my coil banks. The extra gas going into my catalytic converter melted it down. It was after that I read the warning about probes in electrical connector.

Thanks for such quick responses guys. To speak to a few of the things you guys mentioned...... The dealership installed a new battery when the problem first appeared. It didn't seem to be bad because ALL the other electrical accessories worked without a problem. The only thing that didn't work was the starter. The second dealership ran all the diagnostic checks...no problem codes, no battery drain, alternator 14.3 @ 92 amps. Starter checked out,.... everything working fine when they had it.....of course! I have not added anything electrical, or poked around with any of the wires. One guy at the campground had a probe and tested fuses, but everything was okay there too. I'm not sure about the key. There doesn't appear to be a chip in the key unless it is hidden in the plastic handle part.

Is it possible this is related to the security system?

I'm about to call my dealership and see what they suggest. Wish me luck!

5string said:
There doesn't appear to be a chip in the key unless it is hidden in the plastic handle part. ?
It's there, and it's hidden. PassLock II is different than the older PassLock systems. The old ones had a visible chip with contacts, the new ones are hidden and use some sort of black magic.

Is it possible this is related to the security system?
Yes, it's possible. But I would think that would generate a diagnostic code. A bad contact or loose wire is much more likely.

But with all the electronics in our vehicles, it could be just about anything. :rolleyes:

This is what the owner's manual has to say about PassLock:


Your vehicle is equipped with the Passlock@ theft-deterrent system. Passlock@ is a passive theft-deterrent system. Passlock@ enables fuel if the ignition lock cylinder is turned with a valid key. If a correct key is not used or the ignition lock cylinder is tampered with, the fuel system is disabled and the vehicle will not start.

My take from reading this: if it were a theft deterrent failure, it would be the fuel system that is disabled. The vehicle would still crank, but not start.

The owner's manual description is vague (which I'm sure is intentional.) The shop manual goes into much more detail, but I don't have it here with me right now.

However, my recollection is that any problems will be logged with a fault code, and the message center will light up with "Security" just like it does when you are exiting the vehicle.

But I could be wrong, this will require some research into the shop manuals.

-- SS
Yep, it's all the way in Park. Tried that......Tried it with foot on the brake, foot off the brake, sitting in the seat, standing outside and reaching in through the window, holding my breath and clamping my tongue between my teeth! Still wouldn't work. It is working fine right now.........I know it's just waiting until I have something important to go to before it goes out again!

Thanks for the info on the keys. Somehow, there was no owners manual in the vehicle when I got it, and I just recently found this site with the manuals online. Just now figured out how to take the tonneau cover off!!!!

It's baaaaccckkk! Yes sir, the AV would not crank again this morning. Same problem. Plenty of juice in the battery, and all accessories working, but the starter would not engage. This is becoming most annoying to say the least. The tow truck just drove off into the sunrise to take it back to the dealer. If they can't figure out what is going on with this thing, I just might suggest they keep it until they do figure it out, and while they're at it, they can make the payments on it too! I will keep you guys informed as to what happens.

Mongo Ranger,

A remote start switch does not bypass the starter solenoid. It allows you to bypass the keyswitch and all interconnecting wiring.

That aside, a remote start switch would help you to diagnose the problem, since both of your dealers don't seem to be doing much (no surprise).
It does if you clamp to the two big posts. Now I would not recommend using this way to start your AV every time, but it will tell you if it is the solenoid. Make sure you have a heavy-duty switch because when you jump it this way you are running 100% of the power to the starter through the switch. My suggestion would be to just bump it and not actually try to start the AV. It would be the same as running a cable from the positive post of the battery to the starter side of the solenoid.

Heck, I used to do the same thing with a screwdriver. But I would not recommend using a screwdriver on your AV, because you usually end up with sparks flying.
I had a similar problem, but to a greater extreme. Truck would not start but power accs were fine. One night, the truck started, but all dash lights were out and truck would only move in drive (it wouldn't start in 1st, then shift). Another member here posted that he'd had problems with the IGNITION SWITCH. Took it to the dealer with a copy of the post... yup, that's it. Faulty Ign. sw. That could give you intermittant power to run some things and not others. Have your dealer check that, or you can try by cycling the switch from off to start/run a lot (about 1 time out of 12 would the switch actually engage fully --- that's how I got to the dealer instead of having to be towed)

Good Luck,

Mongo Ranger,

I've never had to change a starter on a late model Chevy before, one of the posatives of buying new every three years I guess. But I can tell you every starter I've changed on construction gear would not work they way you suggest. The starter solenoid moves the starter gear into the flywheel, and when the solenoid bottoms out, power is then applied to the starter. If you just put power to the lug on the starter, you shouldn't be able to start the vehicle, you'll only hear the starter run like a motor. Is the Av starter different than this?
Jodiesel, you may be right if Chevy changed their configuration. On every Chevy starter I have worked on the solenoid?s only function is to supply power to the starter. I have not had an AV starter off the truck yet. I might just run to the parts store and have a look at one just to see.
Mongo Ranger,

I thought I'd slide under the Av with my remote starter switch and figure it out for myself. Unfortuneately, on my way to my service truck I made a detour to the fridge for another Corona, which basically squashed the idea of sliding under anything.....
My wife had a similar problem. However nothing electrical worked, we flatbedded it into the dealership. They kept the truck for 3 days and gave it back to us. Resolution: re-charged the battery.

By the way, our truck is just 4 weeks old :(
I would not suspect a pass key fault as that would set a code. I would pay special attention to cable connections and grounds as accessories on the vehicle while they require voltage they take little few amps, the starter on the other hand takes alot - between 125 ans 175 depending on age and heat soak. Poor connections will result in accessories working but no starter operation once large amp flow is called for - this shoudl be easy to detect and repair - are any of the cables loose or can they be moved at all - if so tighten them firmly. (this is a common problem with GM trucks). The starter solenoid does kick out the starter drive to engage the flywheel and as the drive moves out it travels down the main shaft of the armature which has a spiral groove and this begins the starter armature moving resulting in the starter motor turning to turn the engine over, starters have been this way for many years, the only exception would be a starter with a remote solenoid like ford used - those you could apply battery votage straight to the large post on the starter and start the vehicle. It is possible the starter has a bad solenoid or bad armature - does it click when key is turned? or make no sound at all? The neutral saftey switch is also a possibility. In all fairness to the service people if the vehicle starts OK when testing and has no codes it is very difficult to solve a problem you cant duplicate. I am sure this problem will be found and repaired - just be patient. ;)
I had the same strange problem after I washed my AV. It would not start until I jumped it. Then two weeks later I was changing the Hypertech III settings. Once it was complete and asked me to shut the truck off, wait and restart. It would not start again! I was terrified knowing the problems I had read on the site about the hell you go through if this happens while programming.

I disconnected the battery, let it sit for 10 minutes, and then Jumped it again. I have 15,000 miles on the truck so far.
FINALLY!!!!!!! SUCCESS!!!!!!!
I guess that the third time is the charm, but I think the problem has finally been located and resolved. It turned out to be the starter itself, not the solenoid. The purple wire was hot all the way to the starter, but the starter wouldn't engage. The service guy at the dealership told me that if the starter stopped in a certain position, it wouldn't go again, but by tapping on the starter they could get it to work again. (didn't work like that when I tried it, but anyway....) The dealership replaced the starter and all has been okie dokie since then. They assure me that the problem is fixed and I won't have any more problem with that! I'm glad they got it fixed, but I wish they had looked for a further problem beyond the obvious battery problem the first time, especially since it wouldn't jump start. Oh Well..........

Thanks to all you guys that gave suggestions. Most of you were right in that it was starter related. Sorry I left yall hanging for a while, but I wanted to make sure it was actually going to start before I posted success.

I've had a similar yet different problem. One Sunday moring a couple of months ago, I couldn't get AV to run. It would only start if I put my foot on accelerator. I've never had to do this before. When I backed out of garage, and took my foot off gas, it died. It would not run, period. Tried going around block. Died every time I took my foot off gas. I got it back in driveway. I was going hunting. We took another vehicle. When I got home that afternoon, it started and ran fine. It hasn't done this again. My wife said it was because I was skipping church to go hunting.
Last week I had a new problem. I backed out of drive, and radio wouldn't come on. The CD player would eject and take in Cd's. If you pushed the recall button, the time would show, otherwise the radio was blacked out. After running for approx. 5 min, radio popped on. On my way home from work that day, same thing. Only it was warm out, so I wanted to roll down the windows. They would not work either. Again, after running for 3 to 5 min, the radio came on and the windows started to work. It has done this a couple more times. Now is working fine. Any suggestions?
clavin3489 said:
Last week I had a new problem. I backed out of drive, and radio wouldn't come on. The CD player would eject and take in Cd's. If you pushed the recall button, the time would show, otherwise the radio was blacked out. After running for approx. 5 min, radio popped on. On my way home from work that day, same thing. Only it was warm out, so I wanted to roll down the windows. They would not work either. Again, after running for 3 to 5 min, the radio came on and the windows started to work. It has done this a couple more times. Now is working fine. Any suggestions?
I'm guessing you have a problem with the retained accessory power (RAP) which is controlled by a relay. This is what powers most of your accessories. The eject/insert of the CD, and the time recall, will work even with the ignition off. However, playing the radio or CD, or opening/closing windows, runs off the "ignition" power via this relay.

I'm going to guess you either have a bad RAP relay, or a loose connection in the vacinity of that relay.

-- SS
ok, I have a problem that somewhat relates to this thread,

When my engine is cool, my trcuk does not want to start, the starter is going, and it sounds like it is cranking the motor, but it does not sound like my engine is even somewhat wanting to kick over. After 3 or 4 tries to start, it finally does, and once the motor is running it operates normally.

When the engine is hot, this problem seems to disapear, only happens when the motor is cool ???

Tomorrow I will be taking the day off work (kind of) to take my truck to the dealer.

Anyone have any ideas?


BWT, battery is fine, and so is my alternator (according to a meter I have anyway........... :rolleyes:
Just back from the dealer, took my truck in at 8 am, wass ready to go at noon.

Problem turned out to be a new fuel pump.