Weird - Dash Lights

Just finished an aftermarket stereo swap in my 2007 and now my instrument lights aren't functioning (running and with turning on lights). My other interior lights are functioning fine (i.e. HVAC, Shift Console)

Reading post after post for this, it appears that it is most likely a failure in the rheostat. What I didn't come across was the following weird issue. I pulled the dash apart (again) and disconnected the plug behind the dimmer switch then my instrument lights worked...but then my other previously functioning lights did not. I reconnected the plug and, just as before, the instrument lights didn't function while the other lights were fine.

As an interim fix, I left the dimmer switch unplugged since my instrument lights are far more important than the other lights but I want a fully functional vehicle.

I've installed many headunits in my vehicles but have never run into this issue. I used the

$5 Metra 70-1761 Radio Wiring Harness For Toyota 87-Up Power 4 Speaker

Metra 70-1761 kit and I connected the dimmer (orange/white) wire. I heard some people didn't connect this but I like having my display dim when turning on the lights.

Not sure what to do here. I definitely don't want to order a new rheostat if I don't need it.

Another thing I recall was an orange/black wire coming from the old Metra harness. I read that this should not be connected and capped off. I also read that this should be grounded. The new Metra kit did not have this orange/black wire but I did notice that what looks like a white wire with black stripe that is not connected through the harness. I wonder if this needs to be grounded. I'll have to check.

Any assistance you could provide would greatly be appreciated. Thanks.

 

Hopefully this isn't a stupid response but did you check the fuses...?

 

Good question and sorry for not including that piece as one of my troubleshooting steps. I recall fuses in general are located both behind the coin drawer and in the engine compartment. I believe I checked everywhere but to be sure, for a 2007, where is the fuse for the dash lights? BTW, the dash lights work but it's only when I unplug the dimmer (rheostat) switch.

 

you hooked up your ground to the factory dimmer wire if you didnt use a wire harness, if you did use a after market harness , you hook up the dimmer wrong.

 

You blew the rheostat by connecting the orange / white wire.

There are two circuits that are controlled by the Rheostat: The half you probably toasted is the part that goes to the stereo and the combination meter using a brown wire with a white stripe.

The Tacoma is strange in that the Rheostat controls the Ground side of the circuit instead of the Hot side.

 

Thanks Jimmy. So my understanding is tone not connect the orange/white wire from my HU. Correct? if so, do I tape it off or connext elsewhere? BTW I just got a used rheostat in the mail so I'm going to disconnect the orange/white wire and plug the "new" rheostat in.

 

Works now. Capped off the orange white wire and replace ed rheostat.

 

That is what I do cap off the orange and white.

 

Wanted to provide an update on this. As previously mentioned, I disconnected/taped off the culprit wires and replaced the rheostat. One thing that I didn't like with this setup was when I would turn my lights on at night the HU display would not dim so I had to manually change the setting on the HU. As you can imagine, this became old really fast. I then configured the HU to auto dim but it would only let me set only as Day/Night and not a specific time. To finally remedy the issue, I took a 1w diode and connected between the orange harness and stereo dimmer (also orange) wires so that only the stereo would be receiving a signal and not the rheostat. I'm not sure if this truly fixed the issue or if it was coincidence but the HU dims without any impact on the rheostat, at least as far as I can tell.