I found out this evening my dimmer switch stopped working. The speedometer display and MFD are on full bright and I'm sure I've been able to turn them down before. I tried making the adjustment with the headlights on and off and it never mattered. I also recall seeing somewhere on the MFD that I could set it to full bright, but I never even saw that button on any of the screens. Perhaps because it's already detecting full current from the adjustment knob? The switch itself feels normal, has good feel and the detent for full bright is noticable. If I had a multimeter handy I could shoot the resistance through the variable resistor, but I don't, nor do I feel like popping it out of the dash. I guess I have to go back to the dealer now..... :angry: Any ideas?
<div class='quotetop'>QUOTE(Boxster...WRX...Prius? @ Sep 17 2006, 02:14 AM) [snapback]320754[/snapback]</div> No idea
I had the same problem - took it to the Toyota Dealership and they found the wire on the back of the dimmer switch had fallen off. I also lost all light behind the radio controls (seek/scan etc as well as the transmission shifter). They removed the silver vent from the dash to the left oof the steering wheel (it just pulled out - no fasteners) and found the wire loose - not connected to the control. As soon as they plugged it back in everything was fine. Good Luck.
same thought crossed my mind...worth checking anyway, worst case is that the switch went bad. If you're still under warranty and this is a covered item let them do it. If not just order the part and install yourself...look in the articles section for how to install the OEM EV button and it'll tell you how to access that part of the dash.
Way to go Toyotaman! I did exactly what the dealership did to your Prius and I found I had the same problem. After reconnecting the switch, everything works as normal. Total time to perform the repair: less than one minute. Thanks!
It's actually not a rheostat, it's a little low-side PWM unit: . . Click the pic for a big detailed one. The chip is a timer of some sort, which drives the power transistor in a duty cycle varied by the dashboard pot. It runs at about 200 Hz, so you don't see any flicker. The pot is the small round thing in the middle of where the knob mounts; the extra metallic tracks around it are just sliding contacts that let the wipers "fall off" the end to signal the MFD and meters to go full-bright, etc. . _H*
Wow, thanks guys, I had this exact problem come up the other day! My cable fell out as well. That left panel piece wasn't quite a "slide out" on my 2005...it had 4 yellow clips that made it quite a bear to pull out, though it does just pull straight out.
