Where can I find the ECM fuse or relay

The ECM on the jimmy, is located on the passenger side fender well by the overflow tank. But before replace the ECM, inspect the fuel pump and fuel pump relay. The ECM sends power to the fuel pump relay and if the relay has gone bad will cause the fuse to blow which will kill the the power to the ECM, in turn kill the electrical power to the ignition system.

Start by removing the fuel pump relay and swap it with another relay and see if the fuse will blow again, if is does. Disconnect the fuel sending unit wire harness at the frame and see if the fuse blows again, if the fuse stays good. Chances are your fuel pump has gone bad or the fuel filter is dirty/clogged causing your fuel pump to draw more amp and will need to be replaced or the wire harness from the frame to the sending unit has a short which is common on older Jimmy's.

Here is a link to the electrical harness throughout the Jimmy.
http://www.compnine.com/index.php?t=...lid=6872&uid=1

There should be two ECM fuses. Number one powers the injectors and some of the solenoids along with the ECM. Number two or B powers the fuel pump relay and the rest of the ECM including the sensors that provide data to the ECM. Both are 10amp circuits.
You may need to get a shop manual to have the wiring diagrams to troubleshoot the circuits.

check for spark and fuel if you have these things then you will have to have the ecm(computer)checked for codes to see if something has shown up,if you don`t have spark then there may be a code in the ecm if not you will have to check the ignition circuit out to find the problem.if after check fuel pressure with a gage and you don`t have any pressure then it could be a fuse,relay,fuel pump,or even a plugged filter.some places to start.

try disconnecting the battery and leaving it disconnected for a while, then reconnecting it. this usually resets the computer.

Start with checking your fuel pump and injector mini relay. Fuel pump relay is #18 and injectors is #48 and is located in the fuse box under the engine hood.
Also inspect your ECM fuse, the fuel pump get's it power from the ECM fuse and at wost. It's your fuel pump that has gone bad and that is located in the gas tank, but make sure your fuel filter is not to dirty causing fuel restriction and replacing that will address that issue.
Thank you for using fixya and keep us posted.

Sounds like you need new brushes put in the starter,Worn out brushes set no code,does the starter solenoid just click or is it the relay you're hearing?

Look in the fuse box under the hood. Find fuse "ECM B" which is on circuit 120 which excites the fuel pump relay. This is the fuse you want to inspect. The relay pin next to it is controlled by the PCM. The other 2 pins on the relay control the pump and the other the prime circuit.

have a OBDII tester to get the codes. Free at Autozone

the fuse is marked ECM 1 or ECM 2 and is under the hood, as is the fuel pump relay, also these have fuel pump connector problems, did u carefully inspect the pins for heat damage?.

The fuel pump relay is located behind of the glove box. The fuel pump fuse is located in the same box (Relay Center). The fuel pump relay is either the 2nd or 3rd one down in the 2nd row. You may want to check your computer codes and make sure it is not your ECM or BCM as they can shut down ones fuel pump too.