88GMC C3500 ECM-B no power
backyardmec
01-22-2006, 09:10 PM
I have a 88 GMC C3500 5.7 TBI 1ton drw box truck and im not get power to the ECM-B fuse im get 12v to the ECM1 fuse with key on like the book say im geting 0.01v to the ECM-B fuse and the same to the fuel relay and pump I put a new pump and relay and ECM in and trying to go with the book on the wiring but the colors are not the same please help me I need this truck soon to move my self and family thank you for you time
Crasen
01-23-2006, 12:10 AM
I have an 88 with a 350 but mine is a 1500 and I do not have an ECM B fuse, I do have the ECM 1 fuse, and INJ A & B. I would check to see if one of the fusible links are blown at the junction block next to the fuel pump relay. Is the ECM B fuse the Fuel Pump Fuse? If not that would be another thing I would check, I know it is next to the fuel pump relay on a 1500. I know if it was me and I had to get a truck moving i would consider running a wire from the cigarette lighter wire to the fuse to give it power. Just like some people use to tap into the fuse for accesories, but it would work backwards in this case. Definately only a temperary fix, but it may buy you some time to figure your problem out
backyardmec
01-23-2006, 11:56 AM
thank you for your info I bin thinking of doing that but I didnt know if it would be a good idea to put power to the frunt of the fuse because I cant get behined the fuse box I undid the two bolts to it but it dont move but thank you if you know where I can get a good wire diagram
maxwedge
01-23-2006, 12:21 PM
Check autozone.com/repairinfo for a wiring diagram.
dawnnewsome3
01-23-2006, 10:06 PM
I have a 88 c1500 5.7 that had recient fuel pump problems,no voltage to the pump or relay ended up being a bad low oil pressure fuel cut off switch located beside my dist. should be able to disconnect the plug and jump the orange wire and the gray wire with the switch on the fuel pump should have power. the tan wire runs to the dash. by my book this is the same for 88-95 engine controls
Automotive Network, Inc., Copyright ©2025
