99 Yukon won't start

[cdp]

I searched the forum and couldn't find this exact behaviour so here goes:

A week ago I went out to start the truck and got nothing. All lights/electrical come on, no dimming of lights when key is turned but no response from starter. I try 3 more times and finally it fires up like nothing's wrong. Drove to the store and back, no issues.

2 days ago same thing, only this time it won't start no matter how many times I try. Tried putting it in gear and rocking AND jumping. Nothing.

Went out yesterday to get the battery to have it tested (just to rule it out) and decided to try again. Cranks no problem right off the bat.

Took the battery any way and it tests fine. Come home, put battery in and it cranks. Tried again this morning before work and it cranks.

I normally ride my motorcycle so it has been sitting and it is only having trouble on mornings when there has been more moisture in the air.

What can I do to trouble shoot this myself? Or would I be better off taking it to the shop tomorrow and having them look at it?

[GMMerlin]

Originally Posted by cdp

I searched the forum and couldn't find this exact behaviour so here goes:

A week ago I went out to start the truck and got nothing. All lights/electrical come on, no dimming of lights when key is turned but no response from starter. I try 3 more times and finally it fires up like nothing's wrong. Drove to the store and back, no issues.

2 days ago same thing, only this time it won't start no matter how many times I try. Tried putting it in gear and rocking AND jumping. Nothing.

Went out yesterday to get the battery to have it tested (just to rule it out) and decided to try again. Cranks no problem right off the bat.

Took the battery any way and it tests fine. Come home, put battery in and it cranks. Tried again this morning before work and it cranks.

I normally ride my motorcycle so it has been sitting and it is only having trouble on mornings when there has been more moisture in the air.

What can I do to trouble shoot this myself? Or would I be better off taking it to the shop tomorrow and having them look at it?

Was the battery cable loose? A loose positive cable could cause this

[cdp]

I didn't notice, but it COULD have been. I'm going to take it off tonight and clean it and see if it happens again.

[Bob Oney]

If you haven't found the problem yet, try checking the starter relay. I had a similar problem to yours and it was apparently a loose relay. Try taking it out and putting it back in or just wiggling it. Mine has been OK since Jan. 1, but I bought another relay just in case this one fails completely.

[cdp]

That's exactly what it was, the relay was bad. Replaced it and it's been running great since.

[cdp]

Ok, this is still happening. Here's the story so far.

Replaced relay & battery. Was fine for a couple of weeks then started again.
Starter tested bad so replaced that. Fine for a couple of weeks, then happened again.
Replaced battery cables. Guess what?
Cleaned/replaced ground connections.

So far it hasn't happened again, but my mechanic can't be sure it's fixed. When they took it off the tow truck the last time it started right up and they couldn't get it to fail again. Anything else I could be looking at? Seems to be some short somewhere, but it COULD have been the ground connection. Any help?

[GMMerlin]

Originally Posted by cdp

Ok, this is still happening. Here's the story so far.

Replaced relay & battery. Was fine for a couple of weeks then started again.
Starter tested bad so replaced that. Fine for a couple of weeks, then happened again.
Replaced battery cables. Guess what?
Cleaned/replaced ground connections.

So far it hasn't happened again, but my mechanic can't be sure it's fixed. When they took it off the tow truck the last time it started right up and they couldn't get it to fail again. Anything else I could be looking at? Seems to be some short somewhere, but it COULD have been the ground connection. Any help?

If you notice there is a wire that runs from the battery, across the fan shoud to the left underhood electrical center. Check it and see if it is tight.

[cdp]

Originally Posted by GMMerlin

If you notice there is a wire that runs from the battery, across the fan shoud to the left underhood electrical center. Check it and see if it is tight.

It's not tight. Where it runs from the positive terminal to the fuse the wire is stiff. There's a slight bend in the wire coming out of the fuse and across the shroud that has electrical tape around the end. The running across the shroud is loose, but not out of its track.

Could this wire/the bent connection be the culprit? Or the fuse perhaps? The truck has cranked fine the last 5 times, but I'm still nervous about it.

Thanks for the post!

[cdp]

Where the wire bolts into the fuse IS tight, after rereading my last post I realized that wasn't clear.

[70GTORAG]

Originally Posted by cdp

I searched the forum and couldn't find this exact behaviour so here goes:

A week ago I went out to start the truck and got nothing. All lights/electrical come on, no dimming of lights when key is turned but no response from starter. I try 3 more times and finally it fires up like nothing's wrong. Drove to the store and back, no issues.

2 days ago same thing, only this time it won't start no matter how many times I try. Tried putting it in gear and rocking AND jumping. Nothing.

Went out yesterday to get the battery to have it tested (just to rule it out) and decided to try again. Cranks no problem right off the bat.

Took the battery any way and it tests fine. Come home, put battery in and it cranks. Tried again this morning before work and it cranks.

I normally ride my motorcycle so it has been sitting and it is only having trouble on mornings when there has been more moisture in the air.

What can I do to trouble shoot this myself? Or would I be better off taking it to the shop tomorrow and having them look at it?

I have a 94 Yukon with the same problem. I live 1 hour North of the Montana border. My intermittent problem appears from November-March only, when the temperature drops. It started last Winter season and disappeared in the summer until about 4 weeks ago. I have not yet checked anything other than the battery, which was replaced only two years ago. From what I have read, it could be the ignition switch that is mounted in the steering column, and must be dropped to gain access. This can be tested, if you can get a meter on vehicle when it wont start! I have also read that it may be the switch where the key goes in. Maybe someone knows how to troubleshoot these switches?

[cdp]

Went out to go to lunch and it was dead again so I called the shop and they sent a truck. When the truck arrived I tried it again and it was still dead so we pushed it out into the drive so the tow truck could get access to it. On a whim I tried to start it agian and it started. We moved it MAYBE 15 feet with very little rocking. The ignition WAS in the on position the whole time, perhaps that has something to do with it.

[Bob Oney]

Sounds like the same type of trouble I had with the ignition relay on my '99 (see previous threads). Still haven't had any more problems since Jan. 1, but if I do, the first thing I'll check is the relay.
Good luck.

[70GTORAG]

Is thte Ignition Relay your talking about the switch that is mounted in the steering column?

[Bob Oney]

No, sorry I probably described it incorrectly. It is the starter relay in the fuse/relay box under the hood on the left side. Under the top of the box is a graphic description showing where each relay fits. One of them is labeled "Starter" and that's the one that apparently malfunctioned on my '99 Yukon. I still haven't replaced it, but apparently by taking it out and reinserting it, or just wiggling it around, it now makes a solid connection and hasn't failed since Jan. 1. I have heard that something can fail in the ignition assembly in the steering column and can cause the same problem, but I don't think that was my problem.

[cdp]

Originally Posted by Bob Oney

No, sorry I probably described it incorrectly. It is the starter relay in the fuse/relay box under the hood on the left side. Under the top of the box is a graphic description showing where each relay fits. One of them is labeled "Starter" and that's the one that apparently malfunctioned on my '99 Yukon. I still haven't replaced it, but apparently by taking it out and reinserting it, or just wiggling it around, it now makes a solid connection and hasn't failed since Jan. 1. I have heard that something can fail in the ignition assembly in the steering column and can cause the same problem, but I don't think that was my problem.

I think that's exactly my issue. When I remove the fuse the behavior is identical to what I was experiencing. Thank you!