Hello everyone:

I have an Isspro tach R8503 with 3 wires in the back: black, white and red, plus the light bulb. The tach provision plug on my '92 has the following wires (info. taken from the FSM, I have not actually gotten to the plug yet):
Black - to the headlamp switch ground
Orange - to a "node" of other switches
Red - to turn signal flasher
Grey/Light Blue - to SBEC
Well, what to connect to what? And where do you get "juice" conveniently for the bulb?

Thanks to all for any info.

 

That one is in the sticky
Here's the link:

https://www.dieseltruckresource.com/d...d.php?t=173561

 

I got these from the isspro tech manager. Not sure if they pertain to yours. Use at own risk.








.

 

Richie O:
This is exactly what I'm looking for. Thank you so much!

 

You are welcome. I have not hooked mine up yet in the 93. To cold. I got the EV style 4 k tach for that truck. I have the R8503 in my 89. I like it.

 

I am installing a Autometer Trans. Temp Gauge. I know its not a tach, but can I just wire plug to this factory tack harness?? like this:
Black= ground for light and gauge ground both.
Orange= +12 v lighting
Black(note 1)= switched 12v
Grey/lt.blue= leave empty, attach wire from probe to sender on gauge.

 

Sure.

 

Do you have the model number of the Isspro 4K tach?

Thanks,

 

I think it was the Isspro # R5503. My 89 has the R8503