V8david Posted January 28, 2010 Share Posted January 28, 2010 1989 RR 3.5 My heated rear screen is not working, hasn't for quite a while. Put it off for ages but really getting annoying now. Element on the screen is fine, as are the connectors in each corner, as is the wiring inside the roof at the back (pulled down head lining to check) The fuse is fine. There doesn't seem to be any voltage to the fuse though, or the switch. I have swapped the switch for another one but that made no difference. Also, basic I know, but when I pull out and put back other fuses I can see a little spark, as I remake the circuit, but this doesn't happen with the rear demist fuse. As I said very basic but that's my knowledge of electrics. Been clicking about on the net and read alot on other vehicle forums and help sites about rear heated screen relays? Do old RR's have one and if so where is it? Any general hints and tips on where to start looking/checking would be much appreciated. I do have a multimeter which'll obviously help if anyone can tell me what/how to check stuff. Many thanks in advance for any suggestions. Quote Link to comment Share on other sites More sharing options...
rqsall Posted January 28, 2010 Share Posted January 28, 2010 My guess is the voltage sensitive switch. It was the problem on my '91. You can just take it out and short the wires. It is there to prevent the heater from kicking in when the engine isn't running (the lower voltage will prevent the switch from kicking in the heater), but it's a bit pointless as it will not work without the ignition key turned to the "ON" position anyway. The switch is quite expensive too, so I wouldn't bother replacing it unless you can get one from a breaker's yard. It's on the left of the steering column (on a LHD drive car). Pretty difficult to reach, but I have chubby hands ;-) It's a tall yellow "relay looking" device. You won't see it until you have it loose but it has the words "voltage sensitive switch" and a land rover part number spelled on it Good luck. Quote Link to comment Share on other sites More sharing options...
V8david Posted January 28, 2010 Author Share Posted January 28, 2010 Ah! Voltage sensitive switch. I've just been reading my owner's manual and read about it. My next question was going to be "where is that?". Thanks for that rqsall. I'll have a look for that tomorrow, hopefully that'll sort it. Makes sense as the whole circuit seems to be dead. Will report back good or bad... Thanks again Quote Link to comment Share on other sites More sharing options...
g&t Posted January 29, 2010 Share Posted January 29, 2010 HRW relay is on the bulkhead (under hood/bonnet) under the black plastic cover (if still fitted!) which is secured by a 13mm bolt. Should be the third relay, counting from the outside of the car. Quote Link to comment Share on other sites More sharing options...
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