Okay this is a classic..... So the reversing light stopped working recently and I bought a new bulb and chucked it in. Still not working. So I thought I would have a look at the wiring and popped the boot cover off to expose the access to the wiring. In the process of doing this I managed to lock the boot and the key fob would not unlock it. I tried repeatedly but no joy - all doors locked and unlocked okay but the boot was stuck locked. So I opened it manually by operating the catch under the little cover plate from the inside - great I'm in again, but now I'm investigating why the boot lock won't operate and not the original problem of the reversing light Anyway, it gets a bit dark so I leave it for the day. Next day the mrs (its her car) says the rear wiper's now not working. Great . So I assume that I must have disturbed some wiring or something. Anyway now spent the last couple of evenings investigating possible causes and stuff to check online. Then she comes home tonight and informs me that the wiper and boot lock are now working fine - WTF! So now I'm thinking it's some sort of wiring/earthing problem. Does anyone know if there's an earth or wiring loom connector that could affect both the rear wiper and lock solenoid? And possibly the reversing light too - although that is still not working!!! (I'm suspecting it must be the switch on the box but I've almost forgotten about the original problem now - it seems like a long time ago now..... [:^(]) Hope this makes entertaining reading......if nothing else!
I could be all day explaining the full wiring at the boot, but I'm not get yourself a replacement boot lock, including switch these cars are smarter than you think, if the boot is thought to be still open (or open intentionally carrying something) why would you need reverse light shining upwards, rear wiper working ??? it's not seeing the boot fully shut, so the electrics/software takes over !!
Okay so I tested the microswitch and that works fine. The solenoid also seems to work all the time now. The wiper doesn't work, except when the boot is just opened, at which point it travels across and back to the home position - but only if the wiper blade is not on the glass, it doesn't move at all if it is in contact with the glass. So I'm now thinking the problem is that there isn't enough power getting to the tailgate. Neither the reverse light nor the rear fog light works (the display on the dash confirm both of these). I measured the voltage across the pins of the supply connectors and both were around 8.9V - I guess this ain't enough to light the bulb?? So although the lock seems to be working, all other powered components in the tailgate are malfunctioning. Am I even on the right track thinking that the voltage to the tailgate is too low? What could cause that? A bad earth? (I checked the ones in the tailgate and they all look okay). Looks like I might need the full explanation after all....!
You wont have 12v at the lights as it its done by pwm signals so the voltage will vary. Voltages are lower now to prolong bulb life etc Tail lights and brake lights use a single filament bulb and all that happens is voltage is increased to the bulb to increase brightness when braking.
Really - wow, didn't know that. Its been a quite a few years since I used to spend every weekend outside fixing cars and it seems things have changed a lot since then! So it's not a power drain issue then, just something that relates to more than one of the tailgate components. Is there anything else I can easily test with the multimeter (while I have it on loan)?
rear lights on most post 2004 VW's are duty cycled - on off on off constantly so fast you can't see! multi meter don't work unless it's a rear bit of kit! I'm not ruling out there may be an earth wire fault, or broken wire in the loom boy have things moved on!
Ok, cheers for the help guys. Think I'm gonna bite the bullet and take it into an auto electricians, run out of inspiration now. Plus far too cold and dark (and foggy!) out there. Thx again
or just get the rear boot catch (with micro switch) without looking at it, I'm 97% sure this will fix it, I may of seen more than one with this issue. I also know how the central electrics system works
Right an almost hilarious amount of time has passed since I actually got this part (boot lock, 32) but I can report back that it hasn't fixed the problem. I have also checked the earth points in the boot and all look okay. Also checked all the fuses. Is it worth checking all the relays too? Would appreciate any further pointers otherwise planning to drop the car into my local independent garage later this week. Thanks so far and sorry for the delay in trying the suggestions from people!
Turned out to be broken wiring from the tailgate, apparently a common problem on all hatchbacks - which makes sense I guess, never had the same issue on any other golf I've had though, which is about 7 different cars! The spare boot lock will be going into the classifieds now then......
