Alright truck is a 97, I'm getting now power in or out of maxi fuse 22. I've searched everywhere to see where that power in comes from but all I found is why the 22 blows. The fuse isn't blown just no power in. Anyone know where this input power comes from , OR any usual issues? thanks
No Power Maxifuse 22
- Thread starter dthompson
- Start date
Patrick Feeley
Member
It comes from the batteries, through parallel fusible links to UnderHood fuse #17 (50A), through the ignition switch and then to UH fuse #22. If you have power at underdash fuses #17 and #3 with the key in RUN position, then there is a problem between the ignition switch and UH fuse #22. Cheers!
Thanks a ton. I'm fairly certain all under hood fuses were working but will check in the morning. Truck was running and just died. Ok first you said underhood then underdash 17. Coincidence that both are 17 or typo? Thanks
Patrick Feeley
Member
No typo, just coincidence of the #17 fuses. I've attached the appropriate pages out of the 1997 Electrical and Vacuum Troubleshooting Manual (EVTM) that may help you out. If underdash fuses 2, 6, 11, & 14 also do not have power, look for an open circuit between UH fuse #17 and the ignition switch. Hope this helps. Cheers!
Bugman
Active member
#22 maxi fuse under the hood gets it power from the ignition switch on the steering column. Are you checking for power with the key on?
Bugman
Active member
It will be in the ignition switch box under the dash on the column. It is connected to the key tumbler by a rod that activates the switches when you turn the key.
Patrick Feeley
Member
I would look for power at terminal B5 on connector C269 (the one that plugs into the ignition switch). If there is power there, see if there is continuity between terminals B5 and I1 on the ignition switch itself (connector disconnected) when the key is in the RUN position. If there is continuity, reconnect the connector and see if there is power farther downstream at C202, pin 1. After that, you would be at the UH fusebox. Cheers!
Patrick, Do you have a diagram or know which wires are B5 and I1? this wiring crap is all new to me so I'm just going off what your telling me. LOL. I don't see those in the diagram you attached, but maybe I'm overlooking it. Thanks for your help!
zilla68
Active member
its on the top left of the power distribution page he attached, its between numbers 16 and 37 i think it was
Patrick Feeley
Member
Attached is the ignition switch terminal diagram in case you need it. Recheck all your wiring connections to the new switch (or terminals in the connector if you did not change that). If you plan to keep the truck and work on it, I recommend buying the paper version of the EVTM from Helm Inc. It will become your best friend. Cheers!
I quit for the night. The harness side of the connector had a burn mark on the plastic but, still had power at the UH 22 Fuse so I assumed it was ok. Like I said now the WTS and check engine light are flashing and all 4 relays under the hood sound like they are clicking.. I will double check all connections in the morning. Before this I could run a jumper wire to the 22 fuse and the truck would run. Thanks for your help Patrick, I definitely think I need the paper copy. That has been super handy.
Bugman
Active member
Clicking relays usually mean low voltage from the batteries. If the #1 relay is clicking you will be sending power to the PCM and then shutting it off then doing it all over again. That would give you the flashing lights.
Got it fixed! The blinking wts light was #9 fuse blown under the hood. Thanks everyone for your help. Couldn't have done it without you. Got another question for you wiring guru's. The truck is a race truck with an aeromotive fuel pump. Right now it's taped into that #22 fuse. I'm wondering if I shouldn't redo this? what is your thoughts? Thanks
Bugman
Active member
Use the power from the #22 fuse to power a relay and get the fuel pumps power directly from the battery through the relay. That way the pump will only have power when the key is on.
That's kinda what I was thinking, Don't like that the pump is tapped in the way it is. I don't know that it caused my problem here, but rather not take that chance again. A race truck isn't much fun when it doesn't run! LOL! Thanks!
Patrick Feeley
Member
Bugman's idea is the correct way to go. The pump might very well draw more than that circuit is designed for. The switching section of a suitably-sized relay will not draw nearly the same amount of current as a pump. Cheers!
