As some of you know I have been wrestling with the wiring of a trio of Autometer gauges. Everything is pretty straightforward, save for the dimmer. I have access to the back of the dimmer switch, and the gauge lights work perfectly if they are connected to the red/black wire (from battery, turned on by the column's headlight switch). However, if I connect the gauges to the red/black wire, they always stay on full bright (nothing wrong there, since the red/black wire is before the dimmer). What I want is the ability to dim the gauge lights with the dash light dimmer, and to do this I would need to use the red wire. Strangely, as the dash lights are turned up with the dimmer, the gauge lights go down. And, as I turn the dash lights down, the gauge lights go up. Every wire has been tripple checked, and just as I was thinking something was wrong with my car or gauges, I found out that someone else has had the exact same problem. What am I doing wrong? I'm sure it's really, really simple, but I'm not getting it. Thanks for any help!

 

TTT

I know it's not the most exciting question, but I don't know who else to ask. Surely someone (many) has done this successfully and knows the answer. Thanks!!

 

TTT

Last try, before I fabricate my own dimmer switch

 

heh, i confused myself with this a long time ago.... check your ground connections.. i'll grab helm and refresh the wiring diagram in my head.

D

 

There are 2 wires coming out of the dimmer...right? connect the ground of your gauge bulbs to one side and the positive to the other. That should fix you up. Light bulbs are not polarity sensitive so you should be good to go. I did this on mine...works like a champ.

 

Use the red/black as the positve for the lights and the red as the neg. for the lights. All your problems will be solved.

 

Thanks for the help guys. Comparing the info D sent me with your suggestions, it looks like the Autometer instructions were simply super misleading (big surprise, I just wasn't expecting this one). The gauge light ground shouldn't be grounded at all (well, not in the conventional sense). Unfortunately, I combined the gauge ground with the light ground coming out of the gauge pod, so that will create some problems. I may end up using a separate rheastat in the end since I don't want to have to re-wire the pod (I did a good job the first time). I can't very well connect both the gauge ground and the light ground to the dash lights

Anyway, at least I know what my options are and why things weren't working (well, I still don't completely understand the circuit, but oh well). Thanks to everyone for their help Sorry I had to be such a pest on this one

 

I think the dimmer works by increasing resistance to ground (black wire). You will get that opposite dimming effect you described when hooking up the gauge wires in parallel with the red wire, because current flows through path of less resistance. What i reckon ya need to do is hookup one side to the gauge lights to the red/black wire in parallel and the other side the lights to the red wire in parallel.

Then again my electronics knowledge sux. I got rip of dimmer because i wanted full brightness. I shorted out the red and black wire and connect the gauge lights in parallel with the red/black wire.