ECM "B" Fuse

[shaun]

ECM \"B\" Fuse

Does anyone have a schematic that tells what all is on this fuse. I have a 90 jimmy that kept blowing this fuse after I went wheeling one night. It ended up that I had blown my pump and broke my battery. I replaced both and everything was great but then I blew the 10 A fuse for the ecm "B" I replaced the fuse and as soon as I turned on the key it blew. So I replaced it with a 15 and it ran for about 5 mins then blew. I put in another one and as soon as I turned on the key it blew. When I did this witha 25 and a 30 they each lasted about 10 mins. But now as soon as I turn on the key I blow the fuse. WHat could cause this???

 

[zcarczar]

Re: ECM \"B\" Fuse

Sounds like you have a short, or you could have a relay that is getting hot and causing ultra internal resistance causing the fuse to blow. See if you can still run the pump when you jumper the connectors on the relay.

 

[shaun]

Re: ECM \"B\" Fuse

I will try that too. Also Can anyone tell me what the oil pressure sw does and how it works?

 

[dyeager535]

Re: ECM \"B\" Fuse

Oil pressure switch closes somewhere right around 5PSI.

If your fuel pump *relay* fails, it will take longer to crank, but once the switch sees 5PSI, your fuel pump will start working.