No crank

[2004LB7]

undo that 10mm bolt holding that center block on that the ecm wires go into. check for corrosion, damage, melting, etc. check for continuity and power on those lines

 

[Chevy1925]

Fuse block is tore apart an there is no chewed wires or broken wires to ecm your check the #1 #2 fuse in diagram there is no power on them now have 12v coming in power supply to fuse block (the whole fuse block) but don't have any power at the terminals for these 2 fuse that make more sense

This is hard to read.

So you don’t have power at the fuses? As in no power on either side of the fuses? Was the key on when you were checking?

 

[Ron Nielson]

Fuse #1 is the EDU (FICM) fuse
Fuse #2 is the ECM (ECMRPV) fuse
Relay #5 is the EDU Relay

Power comes in from the EDU Relay on Pin 85 on the relay and is grounded by pin 85, which closes the relay. Constant power from Pin #30 passes to Pin #87, then onto the ECMRPV fuse and the EDU Fuse. There should be 12V (battery voltage) on all these circuits with key on. If there is 12V at pin 85 of the relay, there should be 12V on the ECM and EDU fuses. So what has 12V and what doesn't? At least that's the way I see it.

You can't tell if wiring is 'good' by looking - you really have to test, just as James said.

.

 

[ncdmax03]

I've tested the wires an had the whole fuse block disconnected an checked for corrosion an broken wires the wires from the black plug to the ecm is good now yes I have no power on either side of the fuse with key on everything else does iam going to check the relay again tonight when I get back to the shop. Sorry for mis communication

 

[Chevy1925]

I've tested the wires an had the whole fuse block disconnected an checked for corrosion an broken wires the wires from the black plug to the ecm is good now yes I have no power on either side of the fuse with key on everything else does iam going to check the relay again tonight when I get back to the shop. Sorry for mis communication

ah 10-4, then keep following back till you find power. do you have 3v at the fuse?

 

[ncdmax03]

Got 12v power on pin 85 an 87 at edu relay a n thats it

 

[2004LB7]

power should be on 30 and 86. the ECM grounds 85 inorder to close the contacts and send power to 87. are you testing with the relay installed or removed?

 

[ncdmax03]

Relay is removed

 

[2004LB7]

sounds like either you have a buggered ECM or two or more wires shorting together. there should be no power on pin 85

 

[juddski88]

Could also be a bad fuse panel...seen it many many times

 

[Ron Nielson]

Got 12v power on pin 85 an 87 at edu relay a n thats it

Relay is removed

If the relay is not in the circuit or has failed, the activation of the circuit beyond the relay will not happen. You have to have the relay installed in the fusebox to pass power to the next fuses (ECMRPCV, EDU) in line. It is the relay that makes the physical connection of the circuits. No connection, no voltage, just as you have found.

 

[TheBac]

So....swap relays and see what happens...

 

[ncdmax03]

Have done swapped them a few different times an no change I hope to get back in shop here shortly an stick fuse buddy in an Check again havent made it back in shop for working on other junk

 

[ncdmax03]

With relay installed got power on 85 86 87

 

[juddski88]

If you want to be 100% sure it is the fuse panel and not wiring, unplug the fuse panel connectors and test for continuity at that relay socket. But I'm betting fuse panel.

 

[Ron Nielson]

If you have voltage (battery+ voltage) at terminal 87 of the EDU relay, you must have power at the 2 fuses previously mentioned. If not, wire is broken, or chewed, or melted, or ??

 

[2004LB7]

If you have voltage (battery+ voltage) at terminal 87 of the EDU relay, you must have power at the 2 fuses previously mentioned. If not, wire is broken, or chewed, or melted, or ??

and should also mean that the relay is powered and the contacts are closed

or there is an error is the measurement and trying to diagnose an issue over the Internet with what appears to be, sorry no disrespect, someone who either doesn't know how to correctly read the diagrams, use the DOM or both