UrS4 Under dash power posts, question

[Draky]

Finishing the install on my radio system right now and I just realized I don't really know which posts to use... I pulled the covers at the driver's knees (pic below) and was told to use post 15 for ignition source. Is there a post I can use for illumination? The posts are numbered the following:

30, 30a, 58a, 75x, 15a, 75a,15



And almost forgot to mention, this is on a 92 UrS4

Thanks again for the help guys! You guys always ROCK!!

[morris400]

I used 75x for my boost gauge install. Not sure if it helps but thats what i used. It works for the gauge light.

[Draky]

So 75x gives your gauge light when you turn on the lights on the car?

[my2000apb]

if you have a Bentley its easy to chase down the dimmer switch wire

[Draky]

I do not have one.

[Draky]

Anyone with a Bentley care to help me out? Just trying to verify post for illumination, think it may be the 75x.

[scubadave]

you know, you could always try probing that post and others with a test light or DVOM to see what it does when cycling the key, turning on the lights, playing with the dimmer ect.

[EDIGREG]

75x is switched 12v

[dana]

just start probing around with a multimeter and find something that switches on with the lights and drops voltage with the dimmer. Easy.

[Draky]

just start probing around with a multimeter and find something that switches on with the lights and drops voltage with the dimmer. Easy.

Problem is I recently moved and can't find my multimeter.

[dana]

just start probing around with a multimeter and find something that switches on with the lights and drops voltage with the dimmer. Easy.

Problem is I recently moved and can't find my multimeter.

bummer! I can't live without mine.

[morris400]

So 75x gives your gauge light when you turn on the lights on the car?

Yepers

[UrSobsessed]

There should be a source in one of the wire harnesses for the stock HU. If you want it to operate with the head lights, and dim with the rheostat on the instrument cluster, then tap into the wires for the ashtray light. I tapped those for my boost gauge so it goes along with the dash lights.

[EDIGREG]

So 75x gives your gauge light when you turn on the lights on the car?

Yepers

No, 75x is switched 12v. If the ignition is on, it is hot.

Like Dace said, if you want it to turn on with the headlights and dim, ashtray is the easiest source