Which fuse for instrument backlight?

goo · Postby **goo** » Sat Aug 21, 2010 12:13 am

Hey
Turned the headlights on tonight and something popped and the instrument backlights (fan/heater control panel and instrument panel) went out. Headlights still worked fine and demister indicator light and turn indicator lights also working. Probably a blown fuse? But which one?
And why? Did change the headunit last sunday but everything's worked fine since then... Advice anyone?
Cheers
Simon

goo · Postby **goo** » Sat Aug 21, 2010 10:02 am

Ok doesn't seem to have blown any fuses in the cabin fuse box...pulled out the meter, cigar and room fuses and they all are fine. Are there any other fuses in the instrument backlight circuit to check?
Btw, who choose to locate the cabin fuse box THERE??

goo · Postby **goo** » Mon Aug 23, 2010 2:41 pm

Anyone? I'm at serious risk of getting caught speeding at night now! :shock:

taminga16 · Postby **taminga16** » Mon Aug 23, 2010 2:52 pm

Hi,
Check the area around your work on the headlight unit, you may have crushed or caught a cable somewhere there.
Greg.

goo · Postby **goo** » Mon Aug 23, 2010 6:23 pm

Thanks Greg - are you able to be more specific? What wire might I have caught/crushed that runs behind the centre console and affects the illumination of the instrument panel and heater control panel? Obviously the interior light system wire that runs to the head unit is there - i guess also the heater control panel illumination wiring? Should I assume this is a circuit with the instrument panel wiring and that if disrupted might cause the lighting to fail?

Cheers

taminga16 · Postby **taminga16** » Tue Aug 24, 2010 10:16 am

Your original post suggests that you have shorted something 'turned on the lights, something popped' check the work area again. Does the high beam indicator show? park lamps and dash lights share a circuit. Remove the dash light fuse and check if there is power to the live side of the fuse holder.
Greg.

93_Clubman · Postby **93_Clubman** » Wed Aug 25, 2010 4:09 pm

Simon, it shouldn't be any of the fuses in the box on the rear driver's side of the engine bay, but worth a look in case of mods. also, if you haven't already, it would be worth checking the dimmer wheel hasn't been inadvertantly nudged. appreciate it wouldn't explain the complete loss you've had but worth ruling out, before expending time elsewhere.

goo · Postby **goo** » Wed Aug 25, 2010 5:17 pm

Hey paul

I've checked the dimmer wheel (that did occur to me) in hope despite the fact it wouldn't explain why the light was out behind the heater/fan controls. I've also checked the high beam switch - the highbeam indicator comes up on the dash fine so it's not the parker/dash/highbeam circuit...

I'll pull the tombstone and headunit out on the weekend and see if there are any damaged/exposed wires hanging around in there although I would imagine that I should be looking more closely at the wiring around the heater/fan controls than the headunit wiring? Actually, I suppose damage to wiring (to the headunit) which allows the light dimmer function to operate might affect the operation of the backlights...

Do I sound like I'm on the right track?

93_Clubman · Postby **93_Clubman** » Wed Aug 25, 2010 7:05 pm

Sounds like you're on the right track, but it might also be that fitting the new head unit has exposed a weakness in the electrics, not necessarily by exposing a wire, but from overloading or shorting & dated factory or modified electrics.

Btw, don't forget to check the fuses in the engine bay fuse box, just in case there has been past modifcation.

goo · Postby **goo** » Wed Aug 25, 2010 11:13 pm

Awesome news. I've checked the logical fuses in the in-cabin fuse box and the engine bay fuse box.. I'll check the wiring behind the headunit on the weekend but if that's not the answer, what's the next step? An auto electrician or a pro installer for advice?

It might be worth noting that the headunit is still working perfectly well, and is in fact the only source of light in the cabin! The cigarette lighter is working, but I don't think that the ashtray light is working...

Will see what the wiring looks like on the weekend...

fattima · Postby **fattima** » Thu Aug 26, 2010 8:03 am

Hi Simon,

Sorry I missed your post.

Firstly why did you remove the awesome tape deck that was fitted???? :lol:

Are you sure the fuses are OK? If you heard a pop it sounds like a fuse going, have you checked with a test light or multimeter?
Was this the first time you had used the lights since fitting the headunit?

goo · Postby **goo** » Thu Aug 26, 2010 10:34 am

Hey Bruce

Hey, no problems with the tape deck, it's just that my entire music collection has transformed from bits on a magnetic ribbon to mp3 (or their apple equivalents)!

Now when I heard the 'pop' i immediately thought 'fuse'. the headunit also turned off and then back on and the backlights died. i don't have a multimeter but i'll get my hands on one this weekend. It also wasn't the first time I had the lights on since installing the headunit --> head unit installed on sunday night, car fawned over by cheynne on thursday night at the garage (sorry cheynne, its for illustration purposes only) with backlights working, friday at about 6pm there was the pop. Saturday morning I was contorting myself into the driver footwell trying to access the fusebox. I think that's the timeline...

93_Clubman · Postby **93_Clubman** » Thu Aug 26, 2010 11:45 am

fattima wrote:Was this the first time you had used the lights since fitting the headunit?

Simon, Bruce makes a good point here, but I'd add was it the first time you'd turned the lights on concurrently with the headunit being on, or vice versa?

goo · Postby **goo** » Thu Aug 26, 2010 1:05 pm

Paul, I drove home on the sunday night with both on at the same time and did so again a number of times throughout the week. However, I can't recall whether the first time I switched the headlights on when the headunit was already going was friday (when the backlights went out) or before that... Damn memory, although I'm sure its not something people typically take note of...

93_Clubman · Postby **93_Clubman** » Thu Aug 26, 2010 1:32 pm

fattima wrote:Are you sure the fuses are OK? If you heard a pop it sounds like a fuse going, have you checked with a test light or multimeter?

Simon, if you've not already tried the above, I'd do this first, then go back over the work you did fitting the headunit.

Cigarette light has a separate fuse, but ashtray light has wiring going to it, which you disconnect along with power window wires, if removing transmission tunnel console to replace gearbox inner & outer boots.

As for autoelec or pro-sound installer, depends how handy you are with a multimeter or testlight & if you know a good chiro. Btw, removing the seat helps if you need to work under the dash as you can lay on your back & put you're feet up on the rear parcel shelf.