'94 Suburban electrical problem

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T-Max

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1994 Chevrolet Truck K1500 1/2 ton Suburban 4WD 5.7L TBI 8cyl

Last night I was driving it in town in the rain. The wipers weren't working like they should and this happened once before (recently). Instead of just doing one wipe in that position, like they used to, they'd do 3 or sometimes 2. Plus the delay feature wasn't working; they'd just wipe continually. No big deal but then then as I was driving down one street I wasn't sure if my headlights were on (they had been but the roadway looked a bit dark) so I hit my high beams and everything instantly went out, including the engine. I coasted to stop at the curb and it's still there.

After everything went out I shut the headlights off and sat there for a minute. Then I tried to start it. It cranks but does not fire. The electrical system is not working properly at all. The interior light over my head glows VERY dimly and there's a low "squeaking" sound when I turn it on. The radio doesn't work and everything else is just not working right.

I went back today and same thing. I dribbled some gas in the throttle body to see if it would fart but there was nothing. So it seems there's no spark to the plugs. I don't have a partner to crank it while I check for spark but it seems likely there isn't any. I'd bet the fuel pump isn't working either.

I searched the forum for "steering column" because I'd like to take off the cover around the turn signal handle, etc. and see what's going on in there (a short maybe?) but I can't see how to get it off. But I did see Zora's 10-12-2014, 02:02 PM post stating that "the symptoms on other GM vehicles was caused by a bad instrument cluster." My instruments have been a bit flukey for quite awhile, so I'm thinking that could well be the problem. Why hitting the high beams would trigger a complete electrical failure is bit of a mystery to me.

My question is: Do anyone have any suggestions as to how I could get this thing running so's I don't have to have it towed home?

Or any other suggestions as to what this little problem could be (or what to do about it)?

P.S.: I checked for codes and there aren't any.
 
zora said:
have you looked at the fuse box for blown fuses?
http://www.vadengmpp.com/owners-manual/chevrolet/1994-Chevrolet-Suburban.pdf

Also check the wire harness going into the box
No security light on?
Click to expand...

No but I will (check for blown fuses). I looked @ the fuses in the owners manual to see if there was one for the instrument panel that I could remove and hopefully eliminate that as a potential problem but I didn't see that there is one.

What is the "security light"?

Thanks for your help.
 
the "security light" comment was with regard to Passlock antitheft but looking through the owners manual there is no mention of the 94 having it.
 
The Beast is back in my driveway thanks to Triple A (don't ask)

So that little part of the problem is solved. No adverse effects of having left it on the street since Saturday night. I was VERY lucky that it died where it did cuz I got a free parking spot and the cops didn't hassle me for it being there for a couple of days without being moved at all.

I'll look at it later this week (heavy rains coming tomorrow, they say) and if I figure it out, I'll let y'all know.

Any other suggestions will be gratefully accepted and appreciated

I feel MUCH better now that the Beast is back home even if it never runs again.
 
zora said:
glad to hear you got it home, rain in the northeast this morning is incredible, glad it is not snow! The link below provides some generic tests for the 5.7

http://troubleshootmyvehicle.com/gm/4.3L-5.0L-5.7L/index-of-articles-1
Click to expand...

Ya, I'm in central New Jersey, so I'm hip to the rain. Thanks much for that link. I just glossed it over and it looks like it could be very useful. I'll probably check the fuses in a few cuz I'm apparently in a good spot rainwise since it hasn't rained at all here for about 3-4 hours and radar still looks good for awhile longer. I don't expect to find any blown fuses, but it's surely a good early step in the troubleshooting process.
 
Okay, here's the latest.

It runs -- but it ain't right. I certainly wouldn't take it out for a spin because I might just end up having to have it towed again.

I pulled all of the fuses and they are all good. So then I just checked things out a bit and all seemed pretty much okay. When it wouldn't start Saturday night (and Sunday when I went back to it) it clearly had an electrical problem.

Like, for example, the radio wouldn't come on at all. If I tried to turn it on, there would just be a low "whine" that I'd hear coming from someplace. And the dome light wouldn't light up fully; it would have a very low glow (and, again, the "whine" sound). I have the cover off the dome light so that I can see the bulb filament clearly.

So today I found that the dome light would light fully and that the radio came on and operated normally. So I tried to start it up and darned if it didn't start up and continue to run.

I ran it for awhile and learned a few things. For one, the gauges are not working properly at all. Also, when I initially stepped on the brake pedal the seat belt light came on, there'd be the "whine" sound, and the engine stalled. After awhile all that went away, but the gauges still are not working normally AND whenever I step on the brake pedal, the gauges move and the clock display dims.

Also initially, putting the thing in gear seemed to cause it to stall. That's gone away as well although putting it into gear does still seem to cause it to stutter and almost stall.

So it's clearly some kind of electrical problem and I'm guessing that it's related to the wet weather. It was raining pretty hard when the initial event happened and, as I said, the initial symptom was that the windshield wipers weren't operating normally.

It's been dry here (basically) since yesterday ~ 3 pm or so. So things are drying out and now that I've run the Beast up to normal operating temperature, it may be drying itself out and thus things have improved.

I'm thinking it's a ground fault situation related to wetness. Possibly something to do with the brake lights although the instrument cluster is clearly not working properly, if at all.

Edit: I should have mentioned that the tachometer IS working and seems to be working normally. I can't speak for the speedometer because I haven't had it out on the road yet.
 
Last edited:
start with the battery cables both at the battery and the ground and the starter. Check the large wire harness going into the engine compartment fuse box, if you can look under the box too.
 
I started the truck today and it started right up and ran fine but it still has a problem that prevents me from taking it out on the road for fear I won't be able to get it started out there somewhere. It clearly still has a problem.

And it's probably dangerous to drive since I can't know when it's just gonna quit on me.

The wipers are still completely flukey. I have the wiper arms off (more later) but I can see that the motor starts on its own if I turn on the radio, put the truck in gear, or do a lot of other unrelated acts. So I Googled "suburban wiper problem" (without quotes) and if you do that you will find that this is a known (and common) problem with Suburbans (and some other GM products). It's apparently the Wiper Pulse Module, which is inside the wiper motor.

Anyway, I'm thinking that my main problem is unrelated to the wiper problem, but I can't be sure. So I'll keep troubleshooting the main problem.

It's a shame that this problem didn't come up in the summer since the truck mostly sits in the summer since I ride the bike (motorcycle) for the most part anytime I can get away with it (like in warm, dry weather).

As to my wiper arms, I bought a new set of blades a few months ago and I now keep them inside the truck and loosely wrapped in a plastic bag. That's because I previously bought a new set a year or 2 earlier (maybe more) and hardly ever got good use out of them before they were shot. The truck sits outside all day long and the wiper blades simply dry out and get gunked up with leaves and whatnot. So now I keep the arms in the truck and put them on when I need them. It takes just a few seconds to put the arms on, as y'all probably know, so it's no big deal.

I wrap them loosely in a plastic bag just to help preserve and protect the rubber blades from drying out or being damaged.
 
did you check the battery cables at all four connection points as I suggested in a previous post? Can you check the battery voltage with a meter both with the engine off and with the engine at idle and 2000 rpm?
 
zora said:
did you check the battery cables at all four connection points as I suggested in a previous post? Can you check the battery voltage with a meter both with the engine off and with the engine at idle and 2000 rpm?
Click to expand...

Yes. There's a thin ground wire that is bolted to the body just under one of the heater wires, then it is bolted to the top of the frame and can be seen from under the hood. That bolt has a 2nd thin ground wire which then runs from that bolt down under the truck and then upward toward the top of the transmission. That wire is broken at the bottom of its run and it looks like there's a piece of it missing (maybe 2-3 inches?). From underneath the truck it appears to run upward and I'm guessing it's bolted to the top of the transmission somewhere.

The battery ground wire is bolted to the engine and that wire and connection is sound. There is also another thinner short wire which runs off the ground terminal as part of the battery cable and that is bolted to the frame right there. That connection also has a thin black wire which runs into the wire harness under the hood and is clearly the ground wire for something or other.

That connection at the body was loose. I took it off and cleaned things up with a wire brush and reconnected it. I had hoped that this connection was the source of the initial problem, but I guess not because when I had it completely disconnected I checked the dome light and it was still shining brightly. When I had the problem Saturday night, that dome light was barely glowing at all. So it would appear that this loose connection wasn't causing the initial problem.

I plan to rig a short wire with alligator clips to make the connection to that thin ground wire and see what happens once that's done.

Does anyone know anything about that thin ground wire?

Also, I did check the battery voltage when running and it is charging normally. I had previously charged the battery up with my battery charger after having failed to get the truck started Saturday and then again on Sunday.
 
One other thing that occurred to me last night. When I couldn't get the Beast started Saturday night, then again on Sunday when I went back to it, I was wondering whether it wouldn't start due to lack of gas or lack of spark. That is, whether or not the fuel pump was doing its thing and/or there was no spark to the plugs.

I knew there was an electrical problem but I didn't know if I had both spark and fuel, or one or the other, or ????

As for the spark part of it, if I had another person with me I could have simply pulled a plug wire and had my helper try to start it and checked for spark. That's basic stuff.

But I had no helper.

But what I COULD have done (I think) is connected my timing light to a plug wire, taped the trigger down, and then tried to start it with the bulb where I could see it. I think that if it was getting spark, the bulb would flash.

I'll have to give that a try now that I know it's getting spark.

Just a little something to keep in mind.
 
Here's the latest.

Things appear to be back to normal. I made my little jumper cable thing and connected it to the ends of the broken ground cable. Started the truck and everything seems normal -- at least as far as I can tell at this point.

The gauges appear to be operating normally but I can't be absolutely sure of that. The wipers are back to operating normally and I AM sure about that. The dome light is bright, but it's been that way for a few days now. However, the time display on the clock no longer dims when I step on the brake, and that's new.

Also, I couldn't get the truck to stall at all today. I put it in and out of all the gears and no effect. Nothing I did caused it to stall whereas the last time I ran the truck almost everything caused it to stall, even just letting it roll backward on its own.

I even took it for a little spin around the neighborhood and all seemed normal.

Now, the only question I still have is whether this seemingly normal status is due to my "repair" of the broken ground cable, or whether it's simply due to the dry weather we've had for a few days having allowed the Beast to dry out. The initial problem happened after a full day of pretty heavy rain and then my taking it for a drive in the rain.

So I guess I'd say "time will tell." In the meantime, I'll pull up the front floor mat and see if I can see the other end of the broken ground cable which clearly runs up toward the top of the transmission.

Or maybe I can find an electrical diagram that would show where it goes.
 
as you have stated hard to tell what the cause was but you could disconnect the ground you made and see if any of the symptoms come back immediately.
 
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