With ignition on connect a ground to C0663-5 and see if the HRW switch's tell tale light comes on then or not, if not check for voltage across C0661 - 1 and 15
concentrate hard to not mix pins or put ground or measure elswhere cos it's important to find the problem

all i say must be carried out in situ withoout unplugging anything ... let the BCU exposed cos there is work to be done
 
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OK, the troubleshooting for this is quite hard cos the BCU is involved and as long as we dont know for sure it's not due to it's internal circuit we can't conclude... after these last tests if no joy better buy 2 x https://www.autoelectricsupplies.co.uk/product/836/category/210 and i'll tell you how to wire them in for both HRW and HFS then you are sorted, it's quite easy, you'll have to cut the wires at the BCU, crimp some female spade terminals to the wires and connect to the relay
 
sierrafery said:
With ignition on connect a ground to C0663-5 and see if the HRW switch's tell tale light comes on then or not, if not check for voltage across C0661 - 1 and 15
concentrate hard to not mix pins or put ground or measure elswhere cos it's important to find the problem

all i say must be carried out in situ withoout unplugging anything ... let the BCU exposed cos there is work to be done
Click to expand...


No light when earth pin 5

Check volts across pins 1. 15.
Shows 1.4 volts
 
sierrafery said:
OK, the troubleshooting for this is quite hard cos the BCU is involved and as long as we dont know for sure it's not due to it's internal circuit we can't conclude... after these last tests if no joy better buy 2 x https://www.autoelectricsupplies.co.uk/product/836/category/210 and i'll tell you how to wire them in for both HRW and HFS then you are sorted, it's quite easy, you'll have to cut the wires at the BCU, crimp some female spade terminals to the wires and connect to the relay
Click to expand...
Ok my man.
I have found the spare boy will I try that. Or just order the. Relays ???
 
at this point we checked the feed and earth for both heaters at the BCU and that earth to pin 5 you gave was what the switch should do and then the BCU should have closed the internal switch to send feed to C0661 - 15, at this point if you are 100% you made the measurements exactky where i said the BCU is very suspect and continuing the troubleshooting without the BCU being ruled out can be a nightmare... even if it's some other fault not the BCU it can be hidden between headers and connectors which means too many such kind of measurements you've already made are needed while the BCU can be the fault... The best would be to rule out the BCU but for that tester is needed cos a replacement needs complex programming or if you can stay without the vehicle few days better send your's to https://callrova.com/land-rover-discovery-2/ and tell them what's wrong

or you can buy the relays and i'll tell you how to wire them in ...your choice
 
Do you have tester? cos the BCU will not work if it's not programmed.... with ground connected to 0663-5 measure again across 0661 - 15 and earth

and across 0660-1 and 11
 
fireblade7 said:
I have changed b c u
Just the same so will now order 2 relays
Click to expand...
Sorry to jump in here @sierrafery, but replacing the relays is viable for the front heated screen, but unless you have the facilities to replace a relay on the IDM for the rear heated screen, I'd be tempted to look for an alternative fix.
 
brian47 said:
Sorry to jump in here @sierrafery, but replacing the relays is viable for the front heated screen, but unless you have the facilities to replace a relay on the IDM for the rear heated screen, I'd be tempted to look for an alternative fix.
Click to expand...
Based on what was measured untill now IMO the problem is somewhere between the BCU and C0067 for both systems at the same place so the relays will be inserted after that taking over the BCU's swicthing and timing function
 
this message was sent yesterday but for some reason it never posted
I have. Ordered the relays now should get them tomorrow
Mike
so that means relays should be here today
 
Ok, i'm working in a double shift(24H) untill tomorrow, i'll be able to come back with the instructions for the setup untill tomorrow evening i hope... a bit of patience mate and it will be sorted, the new plan is to work at C0067 close to the fusebox
 
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I'll try to make something in my breaks.... on a second thought let the BCU exposed cos we might have to catch up something from there too
 
Sorry mate, i couldnt work on this cos after i woke up i had to keep a good house with some guests and we exagerated with some home made 53* plum brandy :oops:... i'll do it after i'll get sober no worries
 
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sierrafery said:
Sorry mate, i couldnt work on this cos after i woke up i had to keep a good house with some guests and we exagerated with some home made 53* plum brandy :oops:... i'll do it after i'll get sober no worries
Click to expand...
Hahaha all good mate wee need to have a blowout at times
Yea that’s fine. I’m doing other bits and bobs around my yard
 
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