Temp Gauge Help!!

[pjmoreland]

The resistor would have to be removed to be tested. It should measure approximately 85 Ohms.

[JoePolo]

Just took out the gauge, cleaned all the connections and reinstalled with a ground. Still pegs but it’s not stuck I set it back to low prior to putting it in

[JoePolo]

Originally Posted by pjmoreland

The resistor would have to be removed to be tested. It should measure approximately 85 Ohms.

It’s back out I’ll pull that now

[JoePolo]

Originally Posted by pjmoreland

The resistor would have to be removed to be tested. It should measure approximately 85 Ohms.

I cannot get the resistor to read anything, not grounded and no ohm reading. Dunno what’s up.

[pjmoreland]

Originally Posted by JoePolo

I cannot get the resistor to read anything, not grounded and no ohm reading. Dunno what’s up.

Do you have another resistor on your other gauge that you could test and then swap in if it tests good?

[JoePolo]

Fixed thanks everyone. It was a bad resistor on the gauge. I had another cluster in the shed, tested the resistor and installed on the gauge, put it back in and all good.

[pjmoreland]

Originally Posted by JoePolo

Fixed thanks everyone. It was a bad resistor on the gauge. I had another cluster in the shed, tested the resistor and installed on the gauge, put it back in and all good.

That's good news. Does it peg hot when the engine is cranking?

[JoePolo]

Originally Posted by pjmoreland

That's good news. Does it peg hot when the engine is cranking?

Not too sure I didn’t try cranking just turned the key to on position. I will run the truck again tomorrow once my tail shaft plug shows up from Amazon. Had to pull the driveline to redo the center bearing

[dmjlambert]

That is an interesting question pjmoreland asks. If the truck was originally a warning gauge cluster truck the start position of the key switch would have lighted the temp light as a bulb test. pjmoreland mentioned that possibility in post 14 above. I would not want that temp gauge pegging during start.

[JoePolo]

So the saga kinda continues, I think I’m going to need to ohm the new sender. Ran the truck today, not instantly pegged but pegs very quickly after less than 5 min of run time (has water cause when I changed sensor it all poured out on me). Pegs slowly, not instant, then key off….still pegged, key on returns to a normal range, then running it creeps up and pegs again quickly.

Edit: part of my whole issue this whole time with the sending unit, I believe I am hooking up the horn wire to it, I was wondering what the weird junction that splits is for then I went and looked at another truck today. I just need to find the sensor wire now.

[JoePolo]

Found the wire. I did this a while back. I ran it to the sensor on the passenger side head. Dummy.

[dmjlambert]

Here is how many ohms the sender should have at various temperatures.
https://67-72chevytrucks.com/vboard/...53#post7680753

[JoePolo]

Originally Posted by dmjlambert

Here is how many ohms the sender should have at various temperatures.
https://67-72chevytrucks.com/vboard/...53#post7680753

Thanks I pulled the green wire that I ran all the way over to the passenger side sending unit out of loom and temporarily hooked it up to the drivers side sender and will try running the truck again tomorrow, I’m sure this will fix it. I now will need to investigate the original routing of that wire so I can try to run it that way.

[dmjlambert]

There was a wire bundle that plugs into the firewall connector left half (as you are looking at it from standing in front of the truck). It is wrapped with non-adhesive vinyl tape knotted in a clever way to keep it from unraveling at the ends, but when putting the wrapper back on I have used black light duty zip ties. The bundle goes straight up from the firewall plug into a plastic wire gutter, across the length of the wire gutter, then down to a clamp on one of the transmission bell housing bolts on the passenger side. From there the wires come out of the vinyl wrap and go off in different directions engine related, to the coil, starter, temp sender, etc. The temperature sender wire had a cloth wire cover on it to protect it from heat of the engine if it went to the driver side head because it was laying on the engine where the intake manifold meets the valve cover. For the passenger side sender that would be very close to the clamp at the bell housing so it may not need a cloth cover. Here is a picture borrowed from another thread.

[JoePolo]

Originally Posted by dmjlambert

There was a wire bundle that plugs into the firewall connector left half (as you are looking at it from standing in front of the truck). It is wrapped with non-adhesive vinyl tape knotted in a clever way to keep it from unraveling at the ends, but when putting the wrapper back on I have used black light duty zip ties. The bundle goes straight up from the firewall plug into a plastic wire gutter, across the length of the wire gutter, then down to a clamp on one of the transmission bell housing bolts on the passenger side. From there the wires come out of the vinyl wrap and go off in different directions engine related, to the coil, starter, temp sender, etc. The temperature sender wire had a cloth wire cover on it to protect it from heat of the engine if it went to the driver side head because it was laying on the engine where the intake manifold meets the valve cover. For the passenger side sender that would be very close to the clamp at the bell housing so it may not need a cloth cover. Here is a picture borrowed from another thread.

Thanks for such a detailed description, I might end up just heat shrinking it to turn it black then zip tie it to the speedo cable and make the short jaunt to the sender. Instead of trying to snake by the manifold from the back of the motor.

But that did help me in that I need to route my coil wires etc.. through that clamp I see it on the tunnel/firewall. Right now they are just kinda in no man’s land.