adyw

adyw

Member
Having finally finished everything else that did not work. last on my list is the rear heated window. My question having found all the wires at the front and rear of the car is. Are the relays , timing relays or is the system on when switch on and off when switched off.

If it is the latter is it best to replace the relays with a more modern timer relay say 10 minutes

My car is an 1986, 90.
 
I've attached the wiring diagram for my 97 Defender. I know it's ten years younger than yours, but it's possibly similar.
There's a relay on mine and I would expect there to be one on yours. The heating element is going to suck a fair bit of current, so yours is probably also fed via a relay to handle the heavier current flow. I don't often use the heater on my rear window. I don't know if it automatically goes off, but you'd expect it would. Even on a Land Rover :rolleyes: According to the wiring diagram there's a light on the instrument panel, but I can't remember mine coming on. I'll try to remember to check it for you tomorrow and see if I can tell if it auto switches off.
 

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Hi adyw
I recently added a heated rear screen to my 87 90 too.I bought a timed relay for a freelander off ebay(see pics) & it was pretty straightforward to wire in.
STfgVCN.jpg
 

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I'm pleased @Milleme has posted this. It's reminded me to post :eek:
My standard rear window heated screen on my 96 plate 300Tdi 90 goes through the yellow relay on the left of this row of three
20220217_163419.jpg

Obviously, this is in under the fuse cover above the gearbox tunnel.
I've got a light on my instrument panel, but it doesn't work :rolleyes: The rocker switch looks like it might have a light in too, but I can never remember that coming on. Top right symbol. ( I should sort that out)
20220217_163433.jpg

I used the watering can to pour some cold water over the back window and I could just make out the heated lines created by the elements, but not clear enough to get a picture of. The heater still works though. I've consulted the Mrs, knower of all things to be known and forgets nothing. She's driven the Landy as her daily drive to work for about 12 years. She reckons the heated screen does not go off on it's own.
Hope this helps. Very sorry for the delay :oops:
 
Milleme said:
Hi adyw
I recently added a heated rear screen to my 87 90 too.I bought a timed relay for a freelander off ebay(see pics) & it was pretty straightforward to wire in.
STfgVCN.jpg
Click to expand...
I think I'll try to compare the pin configuration of your relay with mine. It would be good to have a timed relay. I wonder if mine does go off and the Mrs is wrong? :D :cool:
I could always sit with my finger on the relay for half an hour or so and wait to see if it clicks off o_O
 
Rear window heats up using the on/off switch. I ‘think’ there’s a temperature sensitive switch behind the dash. Will double check.

Rich
 
@Gun7354 I've just been looking at the circuit diagram for my Landy that I put in post #3 above. There's no voltage sensitive switch in that diagram. I wonder what vehicle your diagram is off? Do you have the full link to the lrukforums thread?
 
I've been doing some more Googling. The voltage sensitive switch is there to stop the heated screen coming on until the car is started. This means that until the engine is running and the alternator is pushing out 13.5 volts, the screen won't come on.
The first relay on the left in my picture in post#6 seems to be the same as the other two (R6HN), so I doubt it's timed.
 
I’m curious about the switch and Dash telltale lights - neither work on mine but the HRW does (although stripey) new bulb in the dash but no joy, can’t tell if the switch is supposed to illuminate?

Odd….
 
slomofo said:
I’m curious about the switch and Dash telltale lights - neither work on mine but the HRW does (although stripey) new bulb in the dash but no joy, can’t tell if the switch is supposed to illuminate?

Odd….
Click to expand...
I think they are supposed to light up. Bloody expensive to buy a replacement!
When I get the chance I'm going to check out my instrument warning light. I can't see it being linked to the illumination on the switch not working. I've tested mine again, just with the ignition on, and I can feel the relay clicking on when I switch the heated screen on, so my circuit doesn't have the voltage sensitive switch in it.
 
thanks for the info gents, i think it is time to remove the front speaker and check out what if any relays i have as i now do have 12v at the rear of the car when the switch is on , but with out the car running, so just a quick check to see if there is anything there at all. if not time for a timing relay
 
adyw said:
time for a timing relay
Click to expand...

I've recently fitted a Nagares TLT 5/12 to my D1 ( after the MFU died ).... on evil bay:-

www.ebay.co.uk/itm/254487698788

12 minute timer - seems a good thing - It does need a momentary sw though - not an on/off. With a momentary, a single pulse turns it on, and starts the timer - another pulse turns it off.... It NVR's when the seperate ignition feed is "lost"...

Another way of checking that the engine is running is to monitor the oil pressure light circuit...
 
Al2O3 said:
I've been doing some more Googling. The voltage sensitive switch is there to stop the heated screen coming on until the car is started. This means that until the engine is running and the alternator is pushing out 13.5 volts, the screen won't come on.
The first relay on the left in my picture in post#6 seems to be the same as the other two (R6HN), so I doubt it's timed.
Click to expand...

Yes, same on my 1994 defender, no timer but only works when the alternator has spun up, so you don't flatten the battery.
Mine takes circa 10 to 15 mins to clear the window all over and is 'on' all the time (unless I switch it off or stop the engine).
 
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