My 01 S80 with less than 1,000 miles is no sun worshipper.

I swear the remote locks fail in direct proportion to the sun shining on the car. First light - works fine. Midday - nothing. By evening, all is OK.

My dealer must think I'm crazy. Performs flawlessly connected to the computer in his state of the art, climate controlled garage.

Has anybody run into this strange problem? OR is it a devious Volvo safety feature designed to prevent exposure to excess radiation?

Signed,

Tanned and stranded in Virginia, USA

When you say mid-day nothing, what do you mean, please describe the failure or what happens when you try to use the remotes?

Rich

I mean "nothing" as in "nothing happens". The remote has no effect.

I have to use the key to open the door - BTW the trunk is a real pain to open by key (what's up with that!).

The key fob(s) have been replaced once under warranty (apparently a known defect in many S80s). I doubt if this failure has anything to do with

them.

My suspicion is that the sensor in the windshield partially de-laminates in the heat of the sun at mid day, then reattaches itselfs as it cools and

settles.

Any thoughts - other than cleaning out my garage?

Al

If this happens with both remotes then my best guess is that you need a new UEM, Upper Electronic Module, its in the rear view mirror. The dealers have a tester to verify the remote working, so if the remote is transmitting and nothing that only leaves the receiver.

UEM - that sounds like the culprit. So its in the MIRROR - I thought it was somehow tied to the windshield. That's good info, thanks.

We've definitely ruled out the remotes - in fact, I'm getting tired of answering that question from dealer and dealer support people.

Makes more and more sense - the mirror will be its hottest in a sealed car in the noon Sun. I see you are in Ffx, VA - so you know we've had unusually full sun with 80+F temps over the last couple weeks.

I'm convinced the UEM is at fault, thanks.

Al

Sounds reasonable, but don't overlook the possibility of [daily] variations

in radio transmissions that can produce sufficiently high background levels

of RF noise that your radios won't communicate well (unless, say, shielded

in the dealer's garage?).

About once or twice per year, mine simply will not work, but it's hardly

a controlled environment...

- Dave; '95 854T, 111K mi

Thanks for the suggestion Dave

I think the heat/sun theory works best for me - its 100% repeatable.

I'm sure there are other ways stuff can happen, and your suggestion is quite valid.

My driver's side door lock fails to work from time to time. It appears to be when it is in the sun. Oddly enough the other 3 doors and boot work, however. Could my problem be in the same league with yours? (01 S80 1.5 weeks old) ...Sam

Your problem is one or two steps further than Al's, he can't get the doors to open at all, in your case they are working, minus one. With the two stage locking, one click of the key fob opens the drivers door (yours fails intermittenly) and the second click open the others. Your problem sounds like it is in the drivers door module, or the drivers door lock, could be rod adjustments or connections. Intermittents are hard to fix and require patients and good communications with everyone involved.