Seeking - Schematic for Fan Light in Speedo...

I had the same problem for years until Forest Goodhart provided me with a wire connection assembly installed behind the dash that cured it, and I'm pretty sure that he will chime in soon to help fix yours too.

Chuck,

First thing is to verify that there is a light and wire at the dash location. Most cars did not have one. The early pre L had a yellow wire running from the fan side of one of the relays to the light in the speedo. If that is not there then you would need to run a wire from the fan relay to the dash and get a bulb holder. The best I can tell from the old wiring diagram is that this was connected to the fan with the higher temp switch.

Forest

If you run your fans with new 10g fused wires from the battery then you will have an unused wire running to the fuse panel that could be used for the fan light in the speedo/tach.  You would need to disconnect the wire from the fuse panel and then extend it to reach the speedo/tach.

Thanks, I am working a fan upgrade now. 

I've got a bulb holder and wire into the back of the Speedo in the proper location.

Mine is an "L" Model (#5357).

I'm not going to argue with the experts, I would have guessed that the light would have been triggered by the LOWER temperature sender, but....

Thanks for the clues.  I'll be work it!

Rocky

(a.k.a. Chuck)

Chuck,

I can't tell which fan the light is connected to on the diagram as the printing is so blurred. I have mine connected to the lowest fan setting but my fans are only a couple of degrees apart in order to minimize the starting surge current.

Chuck,

One of the wiring diagrams show a yellow wire connected to the high temp fan relay and the dash indicator light.  Also shown is a red wire connected to the low temp fan relay with no connection at the dash indicator light.

John

Is the fan light not for the fan into the rear from the AC condensor ?

when you turn the AC switch on ?

Simon

@jb1490 posted:

Chuck,

One of the wiring diagrams show a yellow wire connected to the high temp fan relay and the dash indicator light.  Also shown is a red wire connected to the low temp fan relay with no connection at the dash indicator light.

John

John,

Following that red wire to the other end it somehow becomes a yellow wire, one of two going to the fan light with one shown as not connected. Typical Pantera idiosyncrasy?

Thanks, guys… Appreciate the insight.

I was thinking that the temp sensor provided a ground to the light, but that doesn’t make sense.

Tying it to the output of one of the fan relays to provide a voltage source when the fan is active seems a lot more logical.

It’s really hard to follow those schematics (and I only have one for a ‘74), so I really appreciate the analysis.

John - for some reason I don’t fully recall right now, I have a red connector under the left side of the dash disconnected, with a jumper wire in it…  is that connector possibly in this fan indicator circuit?

Thanks -

Chuck

Chuck,

Yes, that red wire might be for the fan indicator light.

FWIW, the '74 cars did not use a fan indicator light.

John

Forest,

This is what I show: