Resistor for Temp Gauge?

[AstroMotive]

Fiddling with this '70. Had an idiot light dash originally. The guy before tried converting it to a gauge dash with the LMC number gauges. But alas he quit so now I'm trying to figger it out. The gauge pegged when we keyed it up. Sending unit is good. Correct voltage on the circuit. Still trying to figger out why the gauge pegged, but in the mean time, I was looking on here and I saw something talking about a resistor on the gauge and that some require it and some don't. How do I know which is which? The original gauge was in a box but no resistor on it... Thanks in advance for your input.

[pjmoreland]

It is my understanding that LMC gauges do not require an external resistor like the factory gauge had.

The green wire for the idiot light under-dash harness runs from the gauge cluster to the ignition switch and then from there it goes through the firewall bulkhead connector to the temperature switch in the engine head. The purpose of the connection to the ignition switch is to light up the temp idiot light when cranking the engine for bulb functionality verification. When swapping to gauges, this connection to the ignition switch will cause the gauge to peg when cranking the engine. You can pop the green wire connector terminal out of the ignition switch and tape it up so it doesn't short out on anything.

On a side note, do you have the correct style of temperature sender installed in the head? It will have a round sideways connection on it instead of a straight blade fitting.

Have the gauge panel connector wires been repinned as shown in this thread?

https://www.67-72chevytrucks.com/vbo....php?p=9288763

[AstroMotive]

Originally Posted by pjmoreland

It is my understanding that LMC gauges do not require an external resistor like the factory gauge had.

The green wire for the idiot light under-dash harness runs from the gauge cluster to the ignition switch and then from there it goes through the firewall bulkhead connector to the temperature switch in the engine head. The purpose of the connection to the ignition switch is to light up the temp idiot light when cranking the engine for bulb functionality verification. When swapping to gauges, this connection to the ignition switch will cause the gauge to peg when cranking the engine. You can pop the green wire connector terminal out of the ignition switch and tape it up so it doesn't short out on anything.

On a side note, do you have the correct style of temperature sender installed in the head? It will have a round sideways connection on it instead of a straight blade fitting.

Have the gauge panel connector wires been repinned as shown in this thread?

https://www.67-72chevytrucks.com/vbo....php?p=9288763

Right on.

I do have the correct style temp sender.

Thanks for the info on the wiring.

Gonna get back on it on monday.