RangeRovers.net Forum banner

1 - 10 of 10 Posts

·
Registered
1970-1995 Range Rover Classic
Joined
·
139 Posts
Discussion Starter #1
Today, I was reading all the posts/threads on malfunctioning windows on the RRC's and I found many that had a link to another site that apparently used to be valid, but is no longer a valid link:

http://discoweb.org/window/index.htm


I assume this now dead link gave info and pics of the ECU unit and how to troubleshoot cold solders and such. I really wanted to see that, so I did a Google search and came up with another link that shows an ECU from a Disco 1 that the author said might be the same as on some RRC's:

http://www.landyworld.co.uk/discovery-technical/repair-land-rover-discovery-1-rear-electric-windows/


So, as my rear windows have been non-functional for over a year or more, I pulled the center console cubby insert out and buried at the very bottom under masses of confusing wiring was the Window ECU.

It was not like the one in the pictures, the one in my truck is part # PRC 9949.

Sigh.

So, I took it apart anyway and out of its housing, plugged it back in to the harness and worked the windows while watching the relays react. There are 5 relay units and from what I can tell, 4 of them are for the front 2 windows and they activate on UP and DOWN - and both front windows have "one touch" down feature. The 5th relay seems to be for both rear windows (I am not sure - an electrical novice here just sharing experimental observations really) looked closely at all of the solders on the underside - sure enough, I found one that was obviously cracked and possible a "cold solder". I got out my soldering iron and heated up all of the solders pertaining to that 5th relay. I think I fixed it, but not sure until the rear windows work for some period of time - about 10 months ago, one of them worked for about a week, then just quit again and neither have worked since - the front windows have worked 100% reliably since I bought the truck in 2014.

Here are a series of pics of the ECU that will hopefully be of help to others suffering from Window ECU issues:

http://i.imgur.com/7A6wuN4.jpg

http://i.imgur.com/ElxWkzd.jpg

http://i.imgur.com/aKjki6g.jpg

http://i.imgur.com/mAd97WB.jpg

http://i.imgur.com/82JvqpM.jpg

http://i.imgur.com/BKodTXk.jpg

http://i.imgur.com/TUL85rk.jpg

SMD
 

·
Registered
1970-1995 Range Rover Classic
Joined
·
139 Posts
Discussion Starter #2
This is the relay that appears to be for the rear windows:


To clarify what I tried to say in my 1st post, the other 4 relays activate when UP or DOWN is pressed on the front windows - so, if I press DOWN on Drivers side front window, relay 1 activates and when I press UP on that same window, relay 2 activates. On the Passenger side, DOWN activates relay 3 and UP activates relay 4. Again, these are just observations of how *my* ECU is working. I have nothing to compare it to in order to say whether or not it is functioning as it should.


This solder appeared to be defective or failed from age, I actually applied a very small amount of new solder to this joint:



I heated up all of these solders as they seemed to be connected to the relay that (I think) controls the rear windows:




SMD
 

·
Registered
Joined
·
345 Posts

·
Registered
1970-1995 Range Rover Classic
Joined
·
139 Posts
Discussion Starter #4
Update: the rear windows are not working 100% of the time, more like 60% (but this is vastly better than when I started this diagnosis and repair as they had been dead for better part of a year I think) - so, I have intermittent functioning - with no rhyme or reason. I still have the center cubby out and the ECU just sitting in there (in its housing) and I find that when the windows won't work, I can hold one of the window switches engaged to DOWN and shake and/or tap the ECU a bit and they'll start working. So, I guess some part of the ECU is clearly faulty still and I'm looking for a replacement ECU, but they are not commonly found it seems. Maybe I'll cut a hole in the bottom of the cubby insert and run the window ECU harness up through that and leave the ECU in the cubby so that I can reach it (for shaking and tapping purposes!) until I can find a working replacement.


SMD
 

·
Registered
2002-2005 Range Rover MkIII / L322
Joined
·
148 Posts
Remove the ECU circuit board from it's plastic housing and re-connect it to the loom then carefully check the solder connections to the circuit board on all the ECU relays with a magnifying glass. One of mine (the one slightly off set from the others) had several 'dry joints' where they were soldered to the board - This is the one which supplies power to the rear windows.

The windows would work only if I banged hard on the lid of the centre cubby but once I found the dry joints and simply re-soldered them whilst in place, (a year ago) I've had no more issues. The relay's continual vibration eventually shatters the solder - especially where there might have been a poor mechanical joint to the board prior to factory solder application.

Note. You cannot solder over 'air' as there needs to be a good mechanical joint. Either bend the lug to make contact with the copper land or use a short piece of wire to bridge the joint then apply the hot iron first for a few seconds before applying plenty of multi-core resin solder very quickly.

Important: It is essential that you do not move the joint until the solder has completely cured as any movement will crystallize the joint and it will fail again very soon.
 

·
Registered
1970-1995 Range Rover Classic
Joined
·
139 Posts
Discussion Starter #6
HDVideo4K - thanks for chiming in with the suggestions. Question for you: from my pix posted above, do you agree that what I've identified as the "5th relay" is the one that controls the rear windows? Or do I have this wrong? I analyzed the actuation of the relays while the board was out of the housing by working the windows and noted that the "5th relay" seems to be the one that is related to the rear window movement - which is kinda counter-intuitive when you think about it: why would 4 of the relays be devoted to the front two windows and only 1 for both rear windows? I'm pretty sure that I don't fully understand how those relays work and what I'm theorizing is probably not correct………..however, I will remove the board again and do some more testing and heating up of some more of the connections - might get lucky.

When a relay bites the dust - what visual evidence of that is there? I'm not talking about its solders to the board, talking about the relay unit itself - like it's moving parts and that spring that each of them seems to have.

SMD
 

·
Registered
2002-2005 Range Rover MkIII / L322
Joined
·
148 Posts
In my case, it was the relay off by itself. You might be able to flip the relay with your finger nail but re-read my post to see the bit I added to to the end. A clean with a piece of emery paper or #400 wet n dry swiped between the contacts can help too. I'm sure you've simply missed one dry joint. Relays do fail but they often just get stuck and a finger flick can get them going again - this was the case with my interior lamp delay relay - it just needed a clean along with the door and tail gate switches. (the latter can affect your EAS if you still have it so they need to work properly)
 

·
Registered
1970-1995 Range Rover Classic
Joined
·
45 Posts
I had the same problem. It was fixed by simply using disco II switches I got at the junk yard. As I am using a disco center console, I wired in the seat switches too and got rid of the pods. The problem was the switches, not the ECU.
 

·
Registered
Joined
·
2 Posts
Hello, all.

First time post, so I hope I'm not breaking rules by reviving this thread.

Recently purchased a 93 RRC 😍Same issues as above. Took the circuit board out. Had the same dry joint on the same relay as above. Just resoldered it. The rear windows still don't work. However when I now turn on the power, after a few seconds the faulty relay now ocks on without any switch press. And does so till I kill the power.

Any ideas?

Thanks
 

·
Registered
Joined
·
2 Posts
HDVideo4K - thanks for chiming in with the suggestions. Question for you: from my pix posted above, do you agree that what I've identified as the "5th relay" is the one that controls the rear windows? Or do I have this wrong? I analyzed the actuation of the relays while the board was out of the housing by working the windows and noted that the "5th relay" seems to be the one that is related to the rear window movement - which is kinda counter-intuitive when you think about it: why would 4 of the relays be devoted to the front two windows and only 1 for both rear windows? I'm pretty sure that I don't fully understand how those relays work and what I'm theorizing is probably not correct………..however, I will remove the board again and do some more testing and heating up of some more of the connections - might get lucky.

When a relay bites the dust - what visual evidence of that is there? I'm not talking about its solders to the board, talking about the relay unit itself - like it's moving parts and that spring that each of them seems to have.

SMD
Exactly the same issue as you :(

Did you get it going in the end? And how?

Any ideas would be great. Thanks
 
1 - 10 of 10 Posts
Top