GMC Sierra - Popular Questions, Answers, Tips & Manuals - Page 7

battery may have burnt out cell not enough cranking amps for the GMC

Probably the high pressure switch on the accumulator - try disconnecting the connector and jumping the pins to see if the clutch will engage. If that is the problem, DO NOT leave it jumped - replace the switch. If that is not the problem, you will have to check the clutch wiring, relay and fuse for continuity back to the HVAC controls. If that is OK, the problem will probably be in your HVAC control module.

I would start with the ground by the fuel tank that leads to the fuel pump. Corrosion has been known to cuase erratic fuel issues on these trucks. Remove the ground lug (bolt) and scrapand wire brush the frame good ,the ring terminal at the end of the wire and the underside of the bolt. Check the wire end for rot (if it flexes too much) replace the ring terminal and put some silicone or heavy grease under it and attach securely to the frame. If that doesn't work you may need another pump I had to replace my replacement after 5 years (buy a mid range priced pump) not the least expensive from Am*zon or R*ck Auto.

You should go back to school an learn how to spell an how to wright . FULL PRESSURE.THE TECHNISION fuel technician FOUL PRESSURE - fuel pressure . So , what's the point to all this ? Is there a question in all of this ?

Who looked at it ? Dealer ? Did the place's you had look at the vehicle hook up a factory scan tool an view data to door module's an the BCM ? Door ajar is a fuction of the door modules an the BCM - body control module . One of these modules is seeing an input that makes it think door is open . The door ajar indicator system consists of the following components: • The driver door module (DDM) • The passenger front door module (PDM) • The body control module (BCM) • The instrument panel cluster (IPC) • The driver information center (DIC) • The driver door ajar switch • The passenger door ajar switch • The left rear door ajar switch • The right rear door ajar switch • The liftgate ajar switch Driver Door Ajar And Passenger Door Ajar The DDM and PDM receive a discrete input from the respective door ajar switch to indicate the status of the door. The DDM or PDM then communicates this status to the IPC via class 2 message. The IPC, upon receipt of this class 2 message, will illuminate the appropriate door ajar message in the DIC and also send a class 2 message to the radio to activate the door ajar audible warning when the following conditions are met: • The transmission is removed from PARK • The vehicle speed is greater then 8.05 km/h (5 mph) Left Rear Door Ajar And Right Rear Door Ajar The BCM receives a discrete inputs from both the left and right rear door and liftgate ajar switches to indicate the status of the doors and liftgate. The BCM then communicates this status to the IPC via class 2 message. The IPC, upon receipt of this class 2 message, will illuminate the appropriate door ajar message in the DIC and also send a class 2 message to the radio to activate the door ajar audible warning when the following conditions are met: • The transmission is removed from PARK • The vehicle speed is greater then 8.05 km/h (5 mph) Could have DTC'S - diagnostic trouble codes . Looking at data paramiters on the scan tool tool would show what switch is faulty or what part is .

Could also be a a vacuum leak. did they test with a vacuum gauge? Has any service been performed prior to this problem?

If the connectors are wrong, it's the WRONG pump. Return it

Backfiring occurs when uncombusted gasoline gets into the muffler. You will have to figure out if the engine is flooding and why (can be a lot of things - poor ignition, problem with fuel pressure regulator or an injector, vacuum leak, etc.). Existing trouble codes (DTCs) will help you diagnose the problem.

Check the 10 amp pdm fuse in the cabin fuse panel.

The heat cut's out ? The heater blower motor stops working ? Testing the electrical circuit would be the proper way to diagnose . Looking at a wiring diagram an using a DMM - digital multi-meter , an doing amp draw test on the blower motor . The PRND321 an blower motor probably share a ground or power point . Looking at a wiring diagram for both circuit's would show that . Not a short , more likely a loose ground connection . Free wiring diagram's here http://www.bbbind.com/free_tsb.html Enter vehicle info. year , make , model and engine size . Under system click on HVAC then under subsystem click on HVAC controls . Then click the search button ,then the blue link . First blue link is blower motor control circuit . Voltage drop test the blower motor ground .Videos on youtube showing how to diagnose ! Blower Motor Resistor Replacement Wire Splice Splicing Amperage Draw Test Blower Motor Resistor Function and Diagnostics Mastering Voltage Drop Testing with Pete Meier and Jerry Truglia

I would check a few things: Load test the battery. If its got any age on it at all, this could be the culprit. Test the starter. Check for loose connections at the distributor cap. Make sure the rotor in the cap is seated and that the cap is properly seated. Check for loose connections on the battery, the starter and make sure you have fuel pressure on the injector rails (key on, detent the shrader valve .. you should get fuel).

Check the fuel pump relay first. It could be sticking. Under the hood fuse box. Little square switch module. Usually labeled on the lid of the fuse box. To test it,
Swap it with the horn relay if it's the same kind. (Usually is on gm/chevy) start it a few time to see if that changes anything. If not then it could be fuel pump itself

what I think is your calipers are used to being in the outer extension of the piston stroke. when that happens sometimes moisture can set in and oxidize the piston surface, now when you shove the piston back into the caliper to clear the new pad it will stick to the walls of the bore and put to much pressure on the pads then come heat and warp. Next time you replace it buy the preloaded caliper and pad combo an bob your uncle, which mean you should be good. hope this helped.

just takes a tester and some time

Sometimes heat and vibration can cause filters to loosen enough to leak if not tightened enough when initially installed .

Are you sure that it is getting gas, you can take a gas can and pour a small amount down the throttle body (just a teaspoon or less) and see if it starts to run while turning it over. Becareful with the air cleaner off you could get a back fire (fire!) so only use a small amount of gas and have a fire extinguisher near in case you get a flame up. Could be the distributor if it is loose (as it became in my 1988) the distributor hold down fork became bent from over tightening the bolt and it would not stay in position. You will have to slowly turn it if it moved (or use a timing light) to adjust it till it will run there is a connector near the brake booster that needs to be disconnected to properly set the timing.

check unversal on drive shaft. put in neutral and shake drive shaft

only one way to solve the the problem is company service and repair manual which will guide with diagram step by step to fix the problem and you can get the manual from the given link http://toolsnyou.com/

Pull the vacuum line of the transmission modulator valve. If there's oil in the line, the diaphragm in the modulator valve is cracked and engine vacuum is pulling trans fluid into the engine intakee

Post your code s here and I can look them up in my service manuals .