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headlights/wipers/blower/rear screen relay

15K views 19 replies 2 participants last post by  John-H  
#1 ·
morning people

can anyone tell me please if the headlights/wipers/heater blower/indicators and rear screen demist are all on a single relay, and if so where is it located??

Since the colder weather i'm getting an intermittent problem with none of these working. Sometimes they come on of their own accord other times they wont work even switching the ignition on and off.

i know that other owners have had a similar problem in the past and was wondering the outcome.

any part numbers or pics of its postion would be appreciated

Thanks

Matt
 
#4 ·
Sorry, - the plastic trim on the drivers side footwell, next to the door hinge, I think has the micro central electric panel behind with the relay J31 (although I'm getting confuses with LHD and RHD). Check the fuse at the end of the dash for a poor connection:
http://www.wak-tt.com/fuses/fuses.htm
 
#8 ·
Matt,

I should be shot :oops: For some reason I thought it was only your wipers etc., off the stem. As you're getting headlights and fans not working the fault is nearer the main power feed. I'd check the main fuses.

These are the safety fuses that take all the output from the battery bar the starter current.

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Take the cover off, turn things on and give everything a wiggle and a prod. With luck it's only one of the nuts come loose. Check for discolouration of the crimp connection and for signs of melted wire insulation - the loose connection has likely been getting hot. Check the link has not oxidised away too.

This diagram is slightly different to the link I posted above as it's for the earlier car:

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#10 ·
John, typical, when i went out to check the main fuses, switched on the ignition and everything is working. It seems to be happening more first thing in the morning.

the main fuses appear to be all intact and the nuts all tight.

spoke to the guy in the local auto electrics place again and he says its gonna be hard to diagnose if everything is working when he looks at it..he'll need to see it when its not working.

when you said the other relays are in the drivers footwell behind the kickplate, where exactly are we talking....where the bonnet release handle is or actually under the dash?

matt
 
#11 ·
Hi Matt,

Sorry for the delay in replying. I had to wait until I got home to cross reference a few things. Anyway, I've traced through a few items in the wiring diagram and tried to find some pictures for you:

First a word of warning. Be careful you don't short anything out. Some of the fuse ratings are so high you might not blow a fuse but cause a wire to melt and even catch fire - happened to someone fixing their window - the loom shorted and melted together :eek:

The following items and designations connect through from one to another as follows:

A (Battery)
S134 (110A)(Safety fuse)
S132 (50A)(Safety fuse)
30 (Permanent live track - don't short this!!!!)
J59 (Load reduction relay switched from IGN Switch)(Micro Central Electric Panel)
X (Switched track from J59 load reduction relay)
S1(10A)(Fuse panel dash end - Heated mirrors, heated washers)
S2(10A)(Fuse panel dash end - Park light switch)
S224(20A)(Fuse panel dash end - Wiper washer)
S225(25A)(Fuse panel dash end - A/Con)
S226(20A)(Fuse panel dash end) - Rear window defog switch)...

OK, so you've checked the safety fuses.
The load reduction relay disconnects unnecessary load as the engine is being started. Possibly this has a bad connection. It's this that connects through to the fuse box on the end of the dash and may be turning off all your lights, wipers, blower etc.

The relays are on a couple of panels behind the fuse pannel which you can get at by taking the lower dash off. It's also possible one of the bus bars is loose etc.

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http://www.wak-tt.com/mods/boostgauge/boostgauge.htm
 
#12 ·
Right John we may be getting somewhere!!

After checking the safety fuses were all ok i took the kick plate off. The only things i can see are three or four what look like connector blocks, several wires going into the top, and they look to be in 2 pieces. one green, one red, one blue and a brown one...all about an inch and a half square...are these the relays? thought they may have been black boxes that just click in?

anyway, i think the problem may lie with the J59 load reduction relay. I'm saying this cos when i tried the lights etc last night nothing worked again....however...if you switch the lights on to main headlight first, then turn the key to ignition on but not far enough to turn the car over, the sidelights are on then after a few seconds the Xenons fire up and the blowers/wipers/demist etc all work.

am I on the right lines here now??

ps sorry for all the bother!!

Matt
 
#13 ·
Hi Matt,

It's no bother - I'm learning something too. Sorry I've not been back to you sooner but I've been away. I think I might have steered you in the wrong direction for the relay location :? . I've never delved into the relays before on the TT so can only go off the manual etc. I remember seeing something I presumed was a line of relays when I had the kick panel off when I had a window fault and was checking if the power was getting through - it was a long while ago and not then of immediate concern. Given what you've said about them looking like connector blocks I started getting doubts and I again had a look at the pictures and then spotted the "Micro central electric panel" in the picture with the plug in relays. Load Reduction Relay J59, looks to be the black one with "100" written on it, in the picture. I checked in ETKA too and the micro panel of relays attach to the "Fold Relay Panel", by the holes at the ends of the panel, to make one assembly (called by different names in ETKA just to be helpful!). You can see the five bus bar studs hanging down from the micro panel.

Looks like you might have to take off the lower dash to get at it. Chip_iTT posted some useful pictures:

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I'm not sure what's going on with your main beam being necessary before you turn on the ignition. Did you just do this the once or is it repeatable? Anyway, hopefully you'll now find a loose connection or relay etc. Check those main bus nuts are tight. Remember to be careful not to short anything out - e.g. when you get a socket on those nuts!
 
#14 ·
Hi John

It is repeatable...turn the lights switch to on, then turn the ignition on, the lights fire up, turn the key and you're away!! Mad i know!!

I'll try and get that panel off at some point today and let you know my findings. athe pics are a real help.

Matt
 
#16 ·
John...it miraculously sorted itself!!!

I jumped in the car a day or two later and hey presto....everything back to normal!! I'm gonna leave it for the moment but if it starts again then that j59 relay is first option for replacement!!

Matt
 
#17 ·
Apologies for ressurecting this post from the dead but I've finally solved my problem!!

As the post reads, I was having trouble with my headlights/indicators/rear screen demist/blowers/wipers etc not working after starting the car...they were fine with the ignition on but as soon as you cranked her over they all went dead. This was an intermittent problem too which made things slightly more difficult to diagnose.

After replacing relays and checking fuses etc I noticed that if the ignition key was moved back in the barrel everything worked again!! ignition switch!!

This appears to be a fairly rare problem on the TT but a frustrating one!!

Big thanks to John-H for his help and to Gareth at Europerformance in Llantrisant for the patience in looking at different things and for not charging me the earth for it!!

Matt