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jfnar 01-20-2021 11:45 AM

Ignition switch wiring
 
2 Attachment(s)
I had a short that caused the connector to my ignition switch (68 gmc) to get hot. I bought a replacement but noticed that the wire locations don't match the old one. It appears that the colors on the new connector match pictures I've seen in threads on this site but the old one doesn't. Everything was working ok but I had a bare disconnected wire to short out that caused the connector to fry. Should I connect the wires on the new connector like the old one or get the wire colors to match correctly? Thanks for any advice.

jfnar 02-06-2021 12:01 PM

Re: Ignition switch wiring
 
1 Attachment(s)
With all the wires cut, I measure 12.3V on the large red wire at the top in the photo. This wire is the feed from the battery so that should be ok. All others have no voltage except the large brown wire in the center measures 9.6V. Is that correct or does it mean I have a short somewhere? Help please.
Thanks.

jfnar 02-06-2021 12:20 PM

Re: Ignition switch wiring
 
One more question; I have no wire to match up with the small red wire in the picture in the original post. What does that wire go to? Thanks again.

MikeB 02-06-2021 01:47 PM

Re: Ignition switch wiring
 
I found a diagram that shows the following. Check out page 22 here: https://static.speedwaymotors.com/pdf/910510089.pdf

Red -- battery
Purple -- starter
Pink -- ignition
Brown (at 3 o'clock on your picture) -- accessories. This will be hot in "ON" and "ACC" switch positions.

The outer connector at 9 o'clock is labelled as "ground for warning lamp" The inner terminal at 8 o'clock seems to be another ground but it's not labelled.

Do you measure 9 volts to that brown wire at 8 o'clock with or without the ignition switch plugged in?

As for your main question, I'd put all the wires where they were before, since I assume things worked fine before the bare wire shorted to ground.

MikeB 02-06-2021 01:52 PM

Re: Ignition switch wiring
 
Also, which terminal was the small red wire connected to on the old switch? Does it look like a factory wire or something that was added?

jfnar 02-06-2021 04:08 PM

Re: Ignition switch wiring
 
The small red wire is on the replacement connector. On the connector I removed that spot had the 12 ga pink wire. I think the old connector had been jury rigged due to the splices and black tape on it so I don't trust it as a reference. I can match up wires for every location and color except the small red wire. My truck has one less wire than the connector.

jfnar 02-06-2021 04:17 PM

Re: Ignition switch wiring
 
Regarding the brown wire, I measured the voltage with the wires cut from the connector, no switch involved.

Andy4639 02-06-2021 04:44 PM

Re: Ignition switch wiring
 
1 Attachment(s)
Here is the wiring for the key switch.:chevy:

jfnar 02-06-2021 05:51 PM

Re: Ignition switch wiring
 
This gets more confusing every time I work on it. I went ahead and connected all the wires to the corresponding colors on the switch connector. Checked voltage on each lug of the connector. The one connected to the 12 ga red wire is 12.3V, same as the posts on the battery. The lug connected to the 12 ga brown wire now measures 16V. How is that even possible? I checked it several times because I just couldn't believe what I was seeing. I think I'm going to have to trace that wire to see exactly where it goes.

MikeB 02-06-2021 06:08 PM

Re: Ignition switch wiring
 
Quote:

Originally Posted by jfnar (Post 8876108)
The lug connected to the 12 ga brown wire now measures 16V. How is that even possible? I checked it several times because I just couldn't believe what I was seeing. I think I'm going to have to trace that wire to see exactly where it goes.


If it's an auto-ranging voltmeter, are you sure it's 16 volts and not 16 mv?

jfnar 02-06-2021 07:33 PM

Re: Ignition switch wiring
 
MikeB, you're exactly right. I haven't had that meter very long and I didn't even know it would do that. The mV was so small I couldn't see it without my glasses. Thanks for solving the mystery. I won't be able to work on it tomorrow but I guess the next step is to hook the switch up and see if it starts. I'll just tape up the small red wire for now. Thanks again.


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