jess1955

Hi All,

I have a 1955 Oldsmobile 98. I recently switched out the 324 for a 350 Chevy. I need to hook up the temp gauge and i am lost! I have three wires coming out of the gauge. Need to figure out what goes where....

Can anyone help?

Thanks,
Jesse

oldcutlass

I believe, 1 wire is B+, the other is lighting, and the 3rd goes to the sending unit. I would think 2 of the 3 would already be wired unless you/ someone removed the harness.

jess1955

Thank you for the reply. I have been messing with this thing all afternoon. I figured a few things out.... sort of.

The green wire is the fuel gauge. When I hook that up to power the fuel gauge gets a reading.... probably the first time in 20 years. Im not sure its accurate but it jumps to full. Im going to drive the car a bit and see if I get a different read on the gauge after time. Maybe the reason the fuel gauge doesnt work is that this wire supplies the power it needs.

That leaves two wires. I figured out that when I put direct power to the black wire the car turns over.... strange. Im guessing this wire goes to the ignition.

The yellow wire must go to the sending unit. That said I still cant get it to work.

oldcutlass

I changed your title and hopefully one of the guys with a 50's car can point you in the right direction. You really need a wiring diagram.

Ozzie

To the best of my knowledge all the electrically operated gauges on the 1955 have two wires each:

fuel: a yellow 18 ga. which goes to B+ on the switch
a gray 18 ga. which goes to the gas tank unit

temperature: a yellow 18 ga. which goes to B+ on the switch
a green 18 ga. which goes to the engine unit

ammeter: one orange (to junction block) and one red (to a splice with other reds)

There are some grays (18 ga.) on the instrument panel for lighting purposes.

jess1955

Hi Ozzie,

Hope I can ask a stupid question.... what do you mean by B+ on the switch. Where would this connection be?

Thanks,
Jesse

oldcutlass

B+ is the switched 12v source that is only on when the key is on.

Ozzie

Eric has provided your answer.
I am unsure if the Chevy temperature unit in the engine will be compatible with the Olds gauge. Either verify this or use the one from the Olds engine.

oldcutlass

The sending unit has to be compatible to the gauge. If originality is not an issue, I would go with an inexpensive 3 gauge mechanical setup mounted under dash.