r129 Rear window fuse location.

[BULLITTBOSS]

have a problem with my r129 sl 500 rear window demister innoperative,have replaced the melted connector plug from hard top,owners manual shows 30 amp auxillary fuse outside the main fuse board under bonnet but no such fuse on my late 96 exists that i am able to find which manual shows adjacent the brake servo.
any help on location would be much appreciated.
thanks in advance Richard

 

[BTB 500]

Does the handbook match the car? Late 96 would be a 'facelift' model, could be that your handbook is for the previous version.

When you say the HRW is inoperative, what do you mean? Does the switch light up? Is there voltage across the connector plug pins?

The HRW on the R129 is notoriously weak/slow ... putting it on often makes little difference!

Do you know how the plug came to melt previously? That sounds very strange.

 

[BULLITTBOSS]

Mine is the facelift model with the digital climate control panel,the plug for hardtop connection was melted due to loose connection,there is no power now to connector although the light on switch panel works,the handbook does not show my type of heater control panel,so i guess this could be the reason for fuse not where the book shows,........ still looking for fuse as i guess is blown.but dont want to strip interior if someone can tell me the fuse location
Richard

 

[BTB 500]

I'll check my handbook, may not be able to do it till tomorrow pm though.

 

[BULLITTBOSS]

Thanks for that Bill
Regards Richard

 

[dinoy]

keep us informed on final outcome and solution if any.

 

[BTB 500]

Well I checked my handbook (car is a late '96 build, early '97 reg) and there is no mention of an additional fuse for the HRW. The two fuse boxes are the main one in the engine compartment (next to the brake servo), and an auxiliary one in the boot for the roof mechanism. No fuse assignments are given - you are just referred to the list on the lid of each box.

One interesting thing is that the HRW will not operate below a certain voltage (low battery, or lots of other electrical items switched on). But in this case the light in the switch flashes - I guess this isn't happening.

So assuming the fuse(s) mentioned in the main box are OK, looks like it may be tricky to trace.

If you haven't already done this, try checking the voltage across the connector plugs when the HRW is connected (you will have to extend the pins or sockets with something). I seem to remember from playing with mine that there's no voltage at the connector with an open circuit ... some sort of clever electronics?

 

[BULLITTBOSS]

Thanks for that,i have checked the power at socket with voltmeter no power to hard top,switch functions correctly.i will have to connect to star and check circuits,[ star has workshop manual incorperated ] my guess is the relay which i think may be situated in boot somewhere, will keep everyone posted when i find solution.
regards Richard