20 Most Recent 1991 GMC Sierra - Page 7 Questions & Answers

If its for the 4X4 it is on the transfer case

I would go to a salvage yard and get the heater controls out of a salvage vehicle.

I have the same problem with my daewoo because the switch underneath and on top of my brake pedal has a push in type plastic nail so this switch might need to be changed. You should also check all fuses to see if any blowned but if any are blowned that you should have a short somewhere that is making this fuse blowned.

Did you put the correct fluid type in? Check to make sure that you didn't bump any wire connections at the transmission. Check to make sure that the shift linkage is hooked up correctly. Did you make sure that the filters were exactly the same? Some transmissions will have a deep and shallow pan option. Did you get the filter installed correctly. Your question lists two years in it. If it's a 1988 it is possible I think that it may still have a vacuum modulator on it which could be messed up or the vacuum line disconnected.

With the TBI, the AIC solenoid can get stuck and cause problems. It's on the passenger side of the TBI assembly and should have a four wire harness attached.

You probably have either a bad switch or a bad wiper module. The modules are common for failing and are easy to replace. Locate the wiper motor and on it is a black plastic cover held on by 3 or 4 torx headed screws. Unplug it, remove the screws and cover and then you can remove the module and replace it.

sounds like the backup switch has failed, It should be mounted on the
transmission with two wires going to it. Runs about 5 dollars online.

You may have a body throttle position senson. You need a scanner to confirm that. You may have a vacuum leak somewhere around the throttle body. You may have a fuel pump getting weak so I would check fuel pressure. You may have an EGR valve that is partially stuck open.

you have to pull the door panel off and i would first test the motor make sure it is getting power and that the motor really is fried to do that just take a test light hook it to a good ground and poke wires until you find the power if your not getting power then you need to trace that wire and find out y not, but if you are getting power then try to pull/push up on the window as you use the switch to roll it up to help the motor that might not be strong enough to lift the window, if that dont work then you are going to have to unhook the window motor from the door and the window you may not have to take it completely out just enough so that the teeth on the gears arent touching anymore then push the window up into place and bolt the motor back into place to hold the window were it needs to be, or if you have the money check the wires first make sure there getting power and it is the motor and buy and new motor and install it while you have the door all apart and the motor already halfway out.

It could be that since the column moves that much it could be that a connector came loose or a ground wire broke but it sounds like your problem is in the column.

Depending on the wine itself ; you may be able to hear weather it is coming form a front belt or a slipping in the transmission. I would check all fluids and go from their. Sometimes the idler pulley will make the same sound if the belt is worn beyond limit .But usually it will tick if the bearing isn't worn..............Hope this helps.

you need to look for a short in the wiring or either the panel itself....

what it sounds like is the panel is overheating and shutting down

It sounds like your Starter solenoid is stuck, worn out, etc. Either way, have your Starter tested at Autozone, or similar, and replace if it is found to be bad. I’m happy to help further over the phone at https://www.6ya.com/expert/jeremy_69f3cc28d95bf514

light switch needs replaced after checking fuses

No, it does not. I cannot find a cabin air filter listed for a '91 GMC Sierra 1500. Sorry :(

check and replace switch on brake padel

First check the fuse. Second using a multimeter check the blower motor.

tps or throttle position sensor is not adjustable. it only has 2 mounting holes and is preset from manufacturer

your wheel bearings are gone

Things to check...
Check radiator fluid level. Open when COLD. System under pressure when hot. Top up if low.
You need to check the radiator not just the overflow bottle.

If it's already full, then check the heater hose shut off valve. Usually vacuum controlled, against the fire wall. Follow the small hoses back. With engine running, turn the heat control to On or Off and watch for valve to move, may take 30 seconds to move. Fan will not affect this, leave it at low but not off.
If that works OK then check that the interior heat doors / blender are moving when you control the heat.

Was it sudden or come on slowly?
Others may help here too..