Temp gauge wire location

[Sam414]

I have a 77 k20. The previous owner switced the temp gauge to a mechanical gauge and cut the wire for the electrical gauge. I had to get a new cluster and found the proper 77 cluster. I know the wire should be green but could not locate it under the hood. I checked the instrument cluster harness and see a green wire but I lose the wire as I trace it under the hood. When I get a new temp sender where do I run the wire? Thanks in advance for any help.

Sam

 

[1987 GMC Jimmy]

You could cut the wire a little bit down the cluster harness, splice in a new wire, and run it to the sender. Just be certain that you're manipulating the correct wire.

 

[chengny]

Here is where the DK GRN for the temp sender passes through the firewall connector - from the 1977 wiring manual:

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It's the only DK GRN that passes through that transit - so you can be fairly certain that it is the correct lead.

This shows it's location in real time:

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It's in the same slot, they just rotated the block 90 degrees counter clock wise in later models.

Just remove the center bolt, snap the block apart, run a new lead right to that pin using a solderless female spade terminal. Snap the block back together and bolt it up and you're done.

FYI - after passing through the firewall, that lead goes back into the harness loom and exits the loom behind the distributor (along with the oil pressure switches, primary coil leads, etc). After that it is traditionally run along the inside of the LH valve cover and then is lead way up front and over the valve cover to the sender. It is there by design to prevent it from being melted on the manifold. Here are some sucky pictures of what I mean:

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