Strange Electrical Problem

[DaveJ]

Hi there,

Today I went to Camping World and shopped a little. When I came back out and started the motor, I noticed that some of the guages on the instrument panel no longer work. The ones that I know don't work are the speedometer, volt meter, possibly more. The parking brake light no longer lights up.

But the wierd thing is that the automatic tranny seems to stay in 2nd gear now. I'm not totally convinced that there was a problem shifting into higher gears since I only drove a mile or so. Could there be a connection, though? Is it possible that the tranny needs DC from the same failing circiut? Doesn't seem likely. Will work on it more tomorrow and try to find the cause but the shifting issue is the one that's got me the most concerned.

BTW: some things still work: Blinker indicators, wipers, headlights, radio.

I found the fuse panel under the dash so I guess it's time to start working my way though the whole thing to find the bad fuse (if that's what is causing the problems). I wish I could find a fuse layout diagram. Do you suppose an Airstream dealer would have the fuse panel layout documented somewhere for a 92 LY MH?

Thanks for any help.
Dave

[thenewkid64]

An Airstream Dealer may have one, but you will have a better chance at a Chevy dealer if need be. The chassis is a Chevy and the engine and chassis systems are all going to be fed off the main block. Sounds like a blow fuseable link to me.

I have no clue where to look for it, so starting with the fuses is a good start. Pull them and check them. If you can't find it there, there may be a failed breaker. Quite often they are under the hood. I would reccomend a voltmeter to check them.

In the newer Electronic transmissions many of the controls require 12 volt input. The trans may shift from first to second without it, but not go any further without the 12 volts. This is normally a limp mode so you can crawl to a service location.

[DaveJ]

Originally posted by thenewkid64
In the newer Electronic transmissions many of the controls require 12 volt input. The trans may shift from first to second without it, but not go any further without the 12 volts. This is normally a limp mode so you can crawl to a service location.

That's encouraging because it's better than a simultaneous failure of part of the tranny. I'm relieved to hear that there's a connection.

Well...tomorrow I hope I don't make things worst by poking around. I'm pretty good with electronics but the type that I know best is PC boards on the workbench, not crawling underneith and around tight places.

Thanks and I'll let you know what I found out.

Dave

[59toaster]

I'm with Brett. It's all a related electrical problem. The tranny you have may be a 4l80 if it has overdrive. That transmission will go into limp mode if it loses power. Limp mode is 2nd gear. The speedometer doesn't have a cable it's all electronic.

Typical GM wiring is as follows.

Battery power to starter. At the starter the Fuse box pickes up it's feeds. There is usualy 3 fusable links within 10 inches of the connection at the starter. One of those wired feeds the constant 12 terminals. The other feeds the switched. It sounds like the switched is the one your having problems with.


I remember a Post where somebody was having gremilinns like this and it turned out to be a bad ignition switch. Tried finding the post about the bad switch. Looks like it was lost in the forums crash.

The key up top controls a rod that actuates the start switch that is mid way down the steering colum. Check that. heck might have hit some wires with your foot and knocked it loose.

[garry]

Had almost the same problem in a 96 GMC turned out to be the ignition switch. You could turn the key off and restart and most of the time everything would start working.
One difference is my wipers also wouldn't work when this happened.

garry

[DaveJ]

Originally posted by 59toaster
The key up top controls a rod that actuates the start switch that is mid way down the steering colum. Check that. heck might have hit some wires with your foot and knocked it loose.

Want to hear something funny? I noticed a loose bundle of wires near the gas pedal. I've been meaning to tie it up but it was in the way of my foot a few times and I pushed it out of the way a few weeks ago and haven't noticed it since....until now .... <g>