Now that I have verifyied that the tensioners are ok and everything else is running fine, I can turn my attention to a gremlin that started a couple of months ago as a one off but is now increasing in frequency and becoming a PIA.

Basically, sometimes when I lower any of the front windows (doesn't seem to matter how far) the back windows drop and will not raise until some seemingly random point in time when pushing the top up button raises them. If I try to close them by lowering the top and closing it again the top will not latch.

The top and windows work perfectly outwith these times.

I've checked the fluid level in the pump and it is ok (about 1/4 inch above the bottom line with the roof up) and no sign of any leaks anywhere.

Only things I can think of are a sensor somewhere going bad, a poor connection or a dodgy control module.
Anyone got any thoughts before I start spending money on parts to try and fix it ?

Missus just reminded me that it seem to happen only when the boot is pretty full.

Cheers
Tim

 

This is quite an unusual problem.

To help in isolating it, does it happen also when lowering the front passenger window with the passenger doors's passenger window switch?

 

I think so but not sure as I am never in the passenger seat. Difficult to test as it only happens sometimes (although becoming more frequent).

 

OK, it might be worth a few tries.

In the meantime, one somewhat common thread is the security and locking module (SLM) in the boot.

First thing is to check for any dampness in the vicinity of the floor below the boot fusebox. Also check that the black wires bolted to the chassis between the battery and the fusebox and clean and tight and not corroded.

 

Finally got the chance to check the connections to the chassis - all are clean and tight, no moisture under the fuse box.

Problem now happening everytime I open the windows (both sides). I currently have the fuses out so the rears stay up (plenty of rain round here and no garage to store it in).

If it was the locking module would I not see other issues ? I'm pretty much stumped at this point.

 

Before starting to look at expensive possibilities, try a hard reset.

Disconnect the battery and then hold the positive and negative cables together for a few seconds. Then reconnect the battery and reset the windows.

 

I have the same problem, a few others have also had it. It is the one issue on my 99 that I have never been able to fix. I was just talking to my son about this today when I went to the Atlanta auto show. it just eats at me.

I sooooo hope you figure this one out! I would bet you have some good jag mechanics in the UK. 2 independent shops could not figure it out and the dealer wanted to start tearing out all of the seats to follow the wire, it was going to get expensive.

As a data point, mine go down when at least one of the front windows is open and I hit a bump. I can usually put it back up using the top switch, but every now and again I actually have to low and raise the top.

 

 

I have no real idea but try swapping the window relays and see if the problem follows or quicks. Might be a flaky relay.

 

Tried a hard reset but it still drops the rear windows when you lower either of the fronts. I will try changing the relays for new ones (cheap fix if that works but I doubt it).

As far as I can tell there is no connection between the electrics for the front and rear windows on these cars so I am struggling to see why this can be happening. It seems to me that it must be an electrical fault but I just don't see where it can be.

 

Tim, Do you think that you may have a PO syndrome. I just wonder if he/she tried the rear window lowering addition and didn't get all the instruction.


Just a thought. Wayne

 

Hi Wayne. Not sure what you mean by PO syndrome ?

Ive had the car a few years now and it only started doing this late last year. At first it was intermittent but now happens every time I lower either of the front windows so seems to be getting progressively worse.

The other odd thing about it is that the rear windows will not go up again for some time after they have lowered. Eventually they will raise using the roof switch but there does not appear to be any set reason for them doing so. I can be driving for an hour and they will not go up, or they will go up after only 5 minutes, I can leave the car parked and then they will go up after 10 mins or not for hours. This one is weird.

 

Tim, Sorry about that, I meant, Previous Owner. They tend to do things and we have to figure out what it is and sometimes why. On MG's and Triumph's, the wiring was bad from the factory for grounds and the all the add on lights and radios, a true adventure finding trouble. So if you had a PO with a little knowledge and a couple of beers on the weekend, just think what he/she could do with the wiring loom on these cars.


Wayne

 

No worries Wayne. The good thing about this happening now is that the weather here is not suited to top down driving at the moment so not in a huge rush to fix it and can live with the fuses out for a while.

 

Same here Tim, 20 degrees this morning. Jon and I need not rush to get the rams back in. That's another story about a PO, ripped the speaker case out without removing the brace and broke the case

 

Same here Tim, 20 degrees this morning, no need for Jon and I to get the new rams back in. We had a PO rip out the speaker case and broke the bottom bracket, lovely.
Hope you find your problem soon.


Wayne

 

Is that 20 Deg C ?. If so would love that here - we consider that a nice summers day. Currently 7 Deg c here

 

No on the Centigrade more like 12 degrees below freezing, Fahrenheit. I don't remember when England went Centigrade, maybe about the time the pound went from 12 pennies was a shilling. Funny enough I had no problem with that.
My first trip off the base at Chicksands was to Bedford in a MGA and there was a guy still hanging front the gallows on the courthouse steps. I was impressed, not going to be a bad boy here. 1960.


Wayne

 

Hi.


My first thought is a weak battery. Make sure it is fully charged.


Next I would suspect one of the relays driving the top and rear windows, but as your top is working normally I don't think this is the case.


It seems like the window switch somehow may trigger the global opening. If you keep holding the window switch, will the top start to open?


Does the global opening/closing operated by the key in the door operate as designed?


The reason I ask is that this operation is linked to a double microswitch in the door latch via a link rod. If the rod is out of adjustment or the microswitch is malfunctioning the system may go havoc.

 

Hi Oyster

Battery is fine and fully charged - was my first though too but tried it with the battery from my XJR with the same problems seen when it first started happening.

When the windows have dropped through this problem if I open the top and then close it it will not latch so have to latch it manually. All other times top works as normal.

Not sure what you mean by global opening and closing but holding the window switch does not cause the top to open