20 Most Recent 2003 GMC Sierra 2500 Questions & Answers

Hi!! Here is a brake line diagram and description for the 99 K2500 P/U truck you requested. Let me know if you need additional information. Don't forget to rate this post!!

(1) Master Cylinder (2) Master Cylinder Reservoir (3) Pump (4) Brake Pressure Modulator Valve (BPMV) (5) Damper (6) Rear Isolation Valve (7) Accumulator (8) Rear Dump Valve (9) Right Rear Brake (10) Left Rear Brake (11) Left Front Isolation Valve (12) Left Front Dump Valve (13) Left Front Brake (14) Accumulator (15) Right Front Brake (16) Right Front Dump Valve (17) Right Front Isolation Valve (18) Damper

You need to check for fault codes, the check engine light is on because a fault is in the system. Here is how to do a fault code test, no special tools required. Follow the link please. FAQ How to read older GM codes for free

If you look at the upper radiator hose just beside it is a switch that looks like a temp switch (but it is not a temp switch) the switch sends a signal to the computer to mix the fuel. I would change it and see if rough running goes away. The timing is probably ok.

The seal can be changed. You will need to remove pitman arm and remove clip that holds in pitman arm seals. Once clip is removed put a bucket under it and start truck, turn and hold wheel all the way one way and seal will pop out. When installing new one first put some Vaseline on it so you don't tear it on the install. This is also a good time to change your fluid

It needs a clutch pressure plate force is to great do lining & reface flywheel then good to go for a longggggg time

You more likely have an internal problem, namely the High-Reverse clutch pack. If the trans is making the 1 - 2 shift, and your Service Engine light is not on then your speed sensors are working. Judging by the age of the vehicle I would guess that the trans has already been rebuilt at least once (most of the overhauls I do occur at about 150,000 kms) and the failure I see most is the sealing rings have scored the direct drum and led to no third and/or reverse, and of course, no third, no fourth. Want a quick and easy check? Pull the trans dipstick and smell the fluid. It likely has a burnt smell to it.

Is the EGR leaking maybe? Is the idle speed motor working alright?

the syncro rings are poss worn

Tail lights or brake lights?

Transmission stuck in 3rd gear,your transmission might be going out of your truck. ----------------------------------------------------------------------------------Renault CAN Clip V124

get a 20 dollar haynes or chiltons manuel and find the module and coil. always change the ignition module and coil every 4 no more than -5 years to be safe.

Not a transmission expert, but you say you rebuilt it yourself ? What was the original problem ?It could be a blocked valve body or clutch problem, maybe a solenoid.You are bypassing first gear by starting in second, so whatever it takes to make first gear engage is not happening.