Someone at work with an old LT shoebox has bought some LT mirror arms with heated mirrors and was asking me about wiring them in, because he says "they would be similar to the T3 heated mirrors and you have a T3"
For some reason he thinks I'm some sort of "VW go to guy." Like I've ever been posh enough to see a syncro mirror
So I said I would ask here for him. Are they switched or thermostatically controlled?
Is it just be a case of taking a feed from the ignition on side, or wiring a switch into the permanent live on the fusebox?
What would the fuse rating be?
Last edited by Cruz on 04 Nov 2011, 10:47, edited 1 time in total.
I'm pretty sure the heater elements are supposed to be switched like a heated rear windscreen, but I don't have them on my van so I may be wrong. To wire it I would use a switch and a relay. To check the fuse rating on the 30/87 relay side you could just measure the resistance across the terminals and calculate a sensible fuse value - 12v/ohm reading = expected current - go a little bit above that.
yeah - that's right. Good idea to use a blank place for an existing vw switch - the important thing is not to have loads of current going through the switch contacts and let the relay handle that. 6 Ohms means it'll be a bit more than 2 amps with the engine running. I'd put a 5 amp fuse in - that'd blow if it went wrong. I quite often use an existing fused wire (like cigarette lighter so the switch is fused too in case of short circuit - it'll take such a small current from the relay that I reckon that's ok.
I used one of the blank plates in mine to make a sort of diy cruise control switch for set and resume:
looks a bit crap I admit, but it cost about 99p, it works and it makes use of that space!
good point - 30 amp relay with cover both, but probably wise to get a 10 amp fuse since both on together will be very near 5 amps... sorry I forgot about the fact both would be on!
A) Does this wiring digram seem right? It will have a standard 30amp relay instead of 20amp?
B) Does the fuse go on the earth or the permanent live (as shown on the diagram)?
C) Can the earth from the mirrors and switch be routed to terminal 85 on the relay to save space on the earth crown?
D) Would it be any different wiring a rocker switch rather than a push switch? I have a rocker switch that will illuminate when on.
E) There is a blue and brown wire from the mirror. Which is live and which is earth?
Last edited by Cruz on 06 Nov 2011, 17:27, edited 1 time in total.
the diagram looks good - you want the fuse inline inbetween the battery permanent live and pin 30. You can share the earth on pin 85 but make sure the wire returning it is fat enough to carry at least 10 amps - that's when the fuse blows.
Not sure about the colours I'm afraid - I'd test it out and see - not even sure it would matter that much - if I had to guess the brown wires are very often earth on the vws, contrary to everything you're taught about mains wiring!
yes you could do that with the fuse if you have a fuse and relay together. I'm afraid I'm not that up with the early style fuse boxes, but on the later ones there are parallel rows of spade connectors behind it, which connect to the load reduction relay and the battery (X and 30 bus). You want the relay 86 (in your diagram) pin connected to an X connection. Have a look behind your fusebox and see if you can see this row somewhere, probably on the right side as you look at it, and get a multimeter out and test the voltages.
. What rating fuse would that point to?
