I am running an alpine radio that has a dimmer function wire. It hooks somewhere, I assume, into the headlight switch. This should allow the radio illumination to match the dash light illumination when the headlight switch is pulled on. I know the headlight switch has a rheostat that controls the light output for the dash but the switch itself has multiple poles off of it and i have no idea if one of them is responsible for what im looking for.
Anyone have any ideas? the wire diagrams i have in the hayes manual are very small and don't really help
please and thank you
Full Version: Need help on wiring
Grab your DVM and ground the negative test lead, then put the positive lead on each of the power out leads of the switch. (not the bigger power lead into the switch) See which output lead varies voltage when using the dimming function of the switch. That's likely the lead you want to tap into. Slide the radio lead into the connector and double check radio illumination function.
I am running an alpine radio that has a dimmer function wire. It hooks somewhere, I assume, into the headlight switch. This should allow the radio illumination to match the dash light illumination when the headlight switch is pulled on. I know the headlight switch has a rheostat that controls the light output for the dash but the switch itself has multiple poles off of it and i have no idea if one of them is responsible for what im looking for.
Anyone have any ideas? the wire diagrams i have in the hayes manual are very small and don't really help
please and thank you
QUOTE(drdriddle @ Sep 3 2024, 01:16 PM) 
I am running an alpine radio that has a dimmer function wire. It hooks somewhere, I assume, into the headlight switch. This should allow the radio illumination to match the dash light illumination when the headlight switch is pulled on. I know the headlight switch has a rheostat that controls the light output for the dash but the switch itself has multiple poles off of it and i have no idea if one of them is responsible for what im looking for.
Anyone have any ideas? the wire diagrams i have in the hayes manual are very small and don't really help
please and thank you
Well this is pretty easy, at the rear of the switch are two terminals for the rheostat (right next to the terminals). One of those terminals is the input, and the other is the output. Get a piggyback splitter, and put it on the output, then the original wire on the splitter, and the new wire on the splitter.
Click to view attachment
Click to view attachment
QUOTE(davep @ Sep 3 2024, 04:45 PM)
Well this is pretty easy, at the rear of the switch are two terminals for the rheostat (right next to the terminals). One of those terminals is the input, and the other is the output. Get a piggyback splitter, and put it on the output, then the original wire on the splitter, and the new wire on the splitter.
Click to view attachment
Thank you guys. I seriously wish I would’ve asked this question four days ago before I buttoned up the dash. I was tucking the last of the wires away yesterday and realized I had put that last wire aside for ‘later’. Later was last Friday…
@drdriddle
The dimming wire from the headlight switch goes to every illumination bulb in the instruments of the dash. You should be able to grab one of those rather than having to mess with the headlight switch.
The dimming wire from the headlight switch goes to every illumination bulb in the instruments of the dash. You should be able to grab one of those rather than having to mess with the headlight switch.
Yes, connect to any black/blue stripe wire in the dash or center console, it’s all the same circuit.
You can use one of these piggyback spade connectors to add the wire to any illumination bulb spade to connect the dimming wire from the stereo. $0.80 at Digikey.
Piggyback Quick Disconnect Spade at Digikey
Piggyback Quick Disconnect Spade at Digikey
This is a "lo-fi" version of our main content. To view the full version with more information, formatting and images, please click here.