No power from Brown Gauge Feed or Radio Power Wires

[Papa]

I've been trying to resolve my electrical problems and here is what I found today.

1. I was able to directly power my gauges and they work! I thought I'd killed them a couple of weeks ago.
2. I'm not getting power on the brown gauge feed wire or the radio power wire with the ignition in any position.
3. Other 12v switched sources have power as expected.
4. Fuses have continuity - not blown.
5. Wiper motor worked when powered directly using Power Probe II (not fried!).

With a volt meter, I see a brief jump in voltage on the brown gauge feed and radio power wires when the ignition is switched on, but then right back to 0 volts.

Any ideas on if a bad ignition switch could cause the issues I'm seeing? I have a new one I ordered from FF, but don't want to replace it if it isn't the problem.

[Itchief]

My only idea I have is to check connectors to make sure they are still properly seated and that these two wires have not pulled out of the plug sounds like a bad connection to me

Verify that you have 12 volts at the supply side of the fuse and work back towards the dash

If the ignition switch was bad you would not have power on the other circuits

Rick

[Papa]

My only idea I have is to check connectors to make sure they are still properly seated and that these two wires have not pulled out of the plug sounds like a bad connection to me

Verify that you have 12 volts at the supply side of the fuse and work back towards the dash

If the ignition switch was bad you would not have power on the other circuits

Rick

Looking at the wiring diagram, it looks like nothing in the ACC FEED part of the fuse block has power. The 12v switched wire I did have power on was the Orange EFI/COIL wire that comes out of the IGN FEED section of the fuse block and is fed from a different post on the ignition switch. I'll unwrap and check the ignition switch for power at the switch.

[Itchief]

Do you think that you burned a wire when the short happened at the switch or fuse panel

[Papa]

Do you think that you burned a wire when the short happened at the switch or fuse panel

That's entirely possible. I checked the wires at the fuse panel and don't see any sign of arcing or melting and there is no power at the block from the brown feed wire.

[chmhasy]

I've been trying to resolve my electrical problems and here is what I found today.

1. I was able to directly power my gauges and they work! I thought I'd killed them a couple of weeks ago.
2. I'm not getting power on the brown gauge feed wire or the radio power wire with the ignition in any position.
3. Other 12v switched sources have power as expected.
4. Fuses have continuity - not blown.
5. Wiper motor worked when powered directly using Power Probe II (not fried!).

With a volt meter, I see a brief jump in voltage on the brown gauge feed and radio power wires when the ignition is switched on, but then right back to 0 volts.

Any ideas on if a bad ignition switch could cause the issues I'm seeing? I have a new one I ordered from FF, but don't want to replace it if it isn't the problem.

I would ohm out the ignition switched!

[Itchief]

When the short happened something had to fail/melt to stop the current flow

That’s why only part of the circuits are working

There are two feed wires from the ignition switch I would look at the terminal connections at the switch they tend to have some resistance and would melt first and then the switch

Hope this helps

Rick

[edwardb]

Should be easy enough to isolate where the problem is. As you said, Gauge Feed and Radio Power are together on one circuit in the ACC FED section of the RF fuse panel. Powered by the brown accessory feed wire on the ignition switch. That wire should have power with the ignition switch in ACC or RUN. Do the other two circuits on the ACC FED have power? Wiper and Heater? If so, the problem is likely in the fuse panel itself. If not, then likely the ignition switch and could be confirmed by putting power directly to the brown accessory feed wire and/or measuring voltage at the ignition switch with it in various positions.

[Just puttering]

As edwardb said - Do you have 12 volts on both sides of the fuse on those circuits (it is wise to check both sides while you are checking) if not try jumping hot to the dead fuse and see if you get 12v at the gauges, that is an easy place to power that circuit and tests the wiring from the fuse forward. The voltage when the key is moving......... Does it change or stay hot if you move the key slowly and maybe not all the way to run - wiggle it a little?

[PeteH]

Also check all spade connectors in the circuit. I had several that were crimped so hard at the factory that they were severed under the plastic sheath. I soldered in about 8 new spades on the wiring harness, connections to fans and horns in particular were bad. I wrote F5 to have them advise Ron Francis about it.

[Papa]

Problem solved! I removed the ignition switch from the dash and unwrapped the tape and found no signs of arcing or melting at the switch. I put the trusty volt meter on the ACC post and had power at the switch. A closer look and I see that I have the wrong brown wire connected to the switch. After connecting the proper wire, I have power to the fuse block and everything coming off that block. A big ding on the old pride meter, but at least now I can move on. Thanks to everyone that took the time to offer help.

Dave

[GoDadGo]

Congrats on finding this little mishap.

[Itchief]

Good deal I’m glad you were able to resolve the problem

Rick

[edwardb]

Happens to all of us. Glad you figured it out.