20 Most Recent 1990 GMC Suburban Questions & Answers

The actuator will not be on the front differential or drive line, it will be on the transfer case, which is mounted behind the transmission. Follow the front drive shaft back from the front differential, and the component at the rear of the driveshaft is the transfer case. That is where four wheel drive is engaged/disengaged.
I'm not familiar with your vehicle, but if you have a separate lever to engage 4wd, there will not be a fuse for the actuator - it is a manual system. If the 4wd is selected electrically, check that all wiring and connectors on the transfer case are in good condition.

1990 GMC... | Answered on Aug 13, 2018

Rotors and brake calipers.

1990 GMC... | Answered on May 06, 2017

This question is asked so often it should be common answer by now. Check fuse, then ballast resistor (located under hood on heater box), then run hot wire directly to motor for quick test if motor is bad. If everything checks out good, bad heater switch is only thing left.

1990 GMC... | Answered on Jan 13, 2015

There is more than likely a short in the system. The third brake or a wire along the line. Try installing a circuit breaker while you are diagnosing the problem, then start removing bulbs and disconnecting wire harnesses and trying the brakes after each item is removed from the loop. Do one at a time until the circuit stops popping.

1990 GMC... | Answered on Dec 07, 2014

Will it start and or run with a shot of carb spray down the throttle body?

can you hear the fuel pump running?

have you checked to see if there is fuel pressure?

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

1990 GMC... | Answered on Apr 18, 2014

Check inside the drivers and passenger side door jam for the little push in type switch. 9x out of 10 one or the other will be causing the short to the dome fuse. These little **** get rusty and also get alot of wear and tear from the door opening and shutting over and over. These switchs are what causes your dome light to come on when you open your door and or likewise they shut your dome light off when you shut you door. A very good way to test to see if one of these little switchs is the couprate is to take and hook up a voltage light into the negative side battery post after you disconnect the battery negative line.. If your voltage light is on than that would mean that you have a short somewhere in your system. Now, since you already know that you are blowing the dome fuse then your already halfway there. With the light on your votage light still on indicatin a short, unscrew the little switch on the door jam and disconnect the power wire from it. Check to see if the light on your voltage light is still indicating a short, if not then you can be sure that the door jam was the coulprete. Hope this is of help.

1990 GMC... | Answered on Feb 28, 2013

If you look at your starter wires there should be fusiable links there

1990 GMC... | Answered on Feb 23, 2013

It could be many problems. Add some 'chem tool' to the gas tank and drive it for a week or so. Look into getting a tune up.

1990 GMC... | Answered on Feb 06, 2013

try checking your in line fuel filter, if you run low on gas, the pump will suck sediment off the bottom of the tank, and clog stuff up.

1990 GMC... | Answered on Jan 31, 2013

check the cable coming from the back of the alternater going to the battery make sure it has current flowing throw it if not replace it

1990 GMC... | Answered on Jan 23, 2013

The common fault is that the fuel level sending unit is defective inside the gas tank.

1990 GMC... | Answered on Oct 26, 2012

send issue to magicmechanic in orlando--hes a specialist and will reply

1990 GMC... | Answered on Oct 19, 2012

Scroll up and LISTEN to the guy talking about a SHORT. That's what it is. Take off the air cleaner assembly. Lift all the wires up and off the engine, pull the big wire loom a half inch out of the hole it disappears in going through the firewall. Keep doing this until the fuse stops blowing. Took me ten seconds. I still don;t know which wire it is, but I am buying some rubber fuel line and/or wiring loom protector to insulate everything off the valve covers, etc. Be sure to pick up extra 15 amp fuses in case it happens again, and be ready to tell anyone who drives the thing what to do.

Case: 1990 GMC 1500 SLE Suburban. Ran just fine, then the ignition shut off when I hit a random bump or pothole. Cost me a $750 tow before I got on here and did the wiggle test. The fuse stopped blowing. I will update if my fuel line/insulation idea didn't work, but I think it will. I will also tape every exposed wire with electricians tape. . .

1990 GMC... | Answered on Oct 07, 2012

Well, according to my diagrams for 88-94 models, the alternator only uses the red and brown. There are pink-black wires that power some of the sensors and solenoids but should go to a fuse marked ECM in the fuse box.
Have you tried hooking up the harness without using the pink-black wire ?

1990 GMC... | Answered on Aug 31, 2012

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