Our BMW’s windows started to get flaky. They wouldn’t move for a few minutes after the car started, but eventually worked normally, an annoying intermittent problem that wasn’t worth a trip to the repair shop in the hope they wouldn’t work for the mechanic.
I checked the fuse under the hood (#33, 10A) and poked the baby-head-crush safety breaker a few times to no avail.
Then, last night, the windows stopped moving all together. Testing as advised, neither did the sunroof. I found this link and decided it was probably my comfort relay too. This page had a nice list of resources, but the best is gone and only partially available on the internet archive so here’s what I did (and, not to spoil the suspense, this worked).
The panels you need to remove are under the steering wheel. You’re looking at them if you’re lying on your back in the driver’s side foot well, looking up at the bottom of the dashboard. You will need to get through two layers of material to remove the relay, the plastic cover and an aluminum crush panel that protects your knees in a crash. You will need the following tools:
- #2 Philips screwdriver
- Small (1/4″ or so) flat screw driver
- 10mm socket
- Socket extension
- Socket wrench
- Soldering iron
First remove the plastic panel
Step 1 – remove the plastic cover that hides an unsightly screw head with the flat screw driver. You just pry it off.
Step 2 – Remove the now-exposed screw, one of three holding the plastic panel in place.
Step 3 – Remove screw two of three.
Step 4 – Remove Screw three of three. The panel should now sort of flop a bit, but it is still retained by a tight fit and two clips between the dash and the driver’s door.
Step 5 – Pull the plastic panel straight aft, releasing the clips shown and remove it. There is a speaker attached to the plastic panel attached by some wires. If the speaker doesn’t pop out of it’s own accord, you can either pull it out or release the wires.
Step 6 – Remove the knee panel with the 10mm socket. The heads are recessed so you will either need a long socket or an extension to reach them. There are three bolts holding the panel in. As it is removed, lower it gently, there is a metal bracket clamped between the panel and the dash structure that will be loose now.
Step 7 – A previous mechanic had solved the assembly problem of the loose mechanical bracket with some electrical tape. This seemed to work well and made reassembly easy.
Step 8 – Remove the blue comfort relay. This is a bit tedious as I did not remove the bracket first – rather wiggled it out of it’s mount. There are two retaining clips that I depressed that may have aided removal (or not). The relay is pulled “up” – away from the ground and up into the tangle of the dash. This is probably the most tedious step, it is all easy from here.
Step 9 – The comfort relay removed. You can replace it or fix it. If you fix it, pry open the case with your flat screw driver by popping the clips on either side and sliding the blue cover off.
Step 10 – Identify the bad joint. Like other people have found, mine was cracked all the way around.
Step 11 – Solder the joint back together. I was generous with the solder so it might last another 200,000 miles.
Step 12 – After putting the relay back, reinstalling the knee panel, and mostly replacing the plastic panel, snap the speaker back into the back-side (inside) of the plastic panel then replace the screws and cover the unsightly head of the visible one with the plastic bit.
Windows go up. Windows go down.