Convertible rear windows

[toolsisme]

I am having problems getting my rear windows up
After the winter lay up i have just dropped my roof but when i raised it back up everything worked as it should except the rear windows
The front windows drop as normal the roof goes down the front latch locks and the front windows return
Raise the roof the front windows drop the roof raises the latch locks and the front window return but the rears stay down
The audible warning does not sound when you start the raising and lowering process and a new battery has been fitted over winter and front windows reset
I've tested all the fuses and they are all fine
Has anyone got any advice please

Rob

[JimMann]

Hi Rob, you don't say which model of XK you have, X-100 or X-150? However, here is a "Top Tip". When you take the car out of winter storage / lay up, DO NOT adjust anything before driving for at least 10 miles / 16Km to allow the car's brain to reset and relearn its routines. This includes, dropping the top, lowering windows, resetting your radio, etc.

Tell us whether you are troubled by the X-100 or X-150 issues and then we can get back to you.

Jim Mann

[toolsisme]

HI JIm
Sorry it's a 2001 XKR so X100
I have done a few miles before i dropped the roof
Everything else works fine just both rear windows won't come up so i can't see it being both relays or motors gone at once

Thanks for replying

Rob

[JimMann]

Hi Rob, these rear quarter lights are usually very robust. I did experience your issue in the XJS convertible, but usually that was limited to only the one (nearside) rear quarter light. In that case it was the motor jamming in the worm gear section, requiring the motor / regulator to be removed and kicked to release using a major power supply.

In your case, I doubt it is a jammed motor / worm drive as I would suspect a common fault affecting both rear quarter lights. I also suspect that both rear quarter lights are controlled by a single circuit, so potentially a single relay that needs to be reseated.

There will likely be a more experienced knowledge base along shortly to offer additional pointers. Good luck.

Jim Mann

[toolsisme]

Hi JIm
There's 4 relays.Each side has an up and a down relay so i thinks it's a problem with the up circuit but just where is stretching my auto electrical skills
Thanks for your help

Rob

[Astromorg]

There is one fuse common to the four up/down relays that safeguards the supply to their operating coils and that is F1, 5A in the Trunk Fuse Box. That seems like an easy starting point, but as the Down circuits did work, it's maybe not so likely to be the root cause. There's also the two fuses, one to each Up relay protecting the power supplies to the Up relays. F20, 20A and F12,20A, but they too are shared with the Down relays!

Of more concern is that these circuits are 'ground switched, that is, the relay coils have a permanent 12v supply and their operation is triggered by completing the ground wire; the two switches for this (One for Up and one for Down) are in the Body Processor Module. You can see all this here

Before getting to the BPM I would check the Up relays for corrosion on their terminals and also swap them for the Down relays and then I'd start checking voltages and circuit resistance values with a meter.

Come back if none of this helps and you need more, maybe deeper, thoughts and ideas

[toolsisme]

Hi and thanks for all your information
I’ve been working on this all afternoon checking circuits and connections and in the end I swapped the up and down relay’s over and the widows go up and don’t come down
So you were right in your thoughts
I would not have expected 2 relay’s to go faulty at the same time unless they work in tandem or something
Thanks again for your help

Rob

[JimMann]

Hi Rob, a great result - I hoped Astromorg would come in and provide real insight, cheers. What may now be interesting is whether swapping the relays back into the down operation allows them to function or whether something in the operation has taken out the working relays. Which of course would provide you with another problem to solve.

Keep us updated.

Jim Mann

[toolsisme]

After pulling and swapping relays the drivers side worked fine but the other would go down not up or up not down faulty relay?
These are an A1001-X49 the X49 means special specification but no details are available so i ordered a s/hand unit from eBay and it's working
The old unit had no continuity between terminals 3&4 so i ground an old contact breaker file to fit cleaned the contacts and that now works
You have to make the file narrower and thinner to make it fit resulting in only one abrasive side but just turn it over to clean the other contact face
I now have a spare relay and a "special"tool
These relays are in so tight i first though they were none removable even after prying back the retaining clips
Thanks for everyones input with this matter

Rob

[JimMann]

Hi Rob, well done. Shows the collective power of the forum when an issue can be highlighted, discussed and ultimately resolved.

Jim Mann

[MarkX]

I've read this dialogue with interest - good to see that the cause has been found! Alas since reading the first post I have started to get an intermittent fault with the back window being a tad reluctant to go down or going down half way - where are the relays located?

Many thanks

Mark

[toolsisme]

Hi
They are in the boot with the battery
Pull the left hand cover to reveal the battery and the relay/fuse box will be right in front of you nearest the rear of the car
Lift the lid off this and you will see all the relays and fuses
The relays you want are the forward most row to the right and they are Micro relays (smaller than all the others) 4 of them together so easy to spot
I found them really tight as there are retaining lugs at each side and even with these wedged clear they were a swine to pull I've still got blisters on my finger
You can test the relays quite easily just look up 5 pin relay testing on you tube

Good luck

Rob

[MarkX]

Thanks Rob, I plan to swap them over in the coming days.