Hey guys, I have a 1987 325, 220k miles, has treated me very well over the years... anyway, an interesting problem has come up with some lights and my A/C, and I was wondering if you guys might have any idea what's gonig on.
I tried to cut my A/C on a couple of weeks ago, and no cold air came out. Beyond this, there was no "hum" or any kind of noise or engine dropout that I'm used to when cutting the A/C on. As it turns out, I also discovered that all of the backlights behind the heating/cooling controls aren't lighting up. The digital clock and radio are still working, and the "recirculate" button still works properly and is still sufficiently backlit. I checked my freon levels, and they're fine. So basically, I have no A/C, and no backlights behind the heating and cooling controls (aside from the "recirculate" backlight). Also, possibly an unrelated problem, my "coolant" light on the overhead panel is on probably 2 out of 3 times when I cut my car on, despite having sufficient coolant levels.
I had my wiring harness replaced about 20k miles ago, and the A/C cycler replaced a couple of years ago, and it worked last year, so I'm wondering what could be going on here. I looked at the fusebox, and on a VERY quick glanceover, none of the fuses looked burned out. Any ideas what might be going on here? And if it sounds like it actually is a particular fuse, which one would it be?
Thanks for your help.
- Ross
Interesting Electrical problem - read on
Moderator: martauto
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Brianmoooore
- E30 Zone Team Member
- Posts: 49358
- Joined: Mon Jan 10, 2005 11:00 pm
Fuse 20 is aircon.
Check to see if the compressor clutch pulls in when you switch thre aircon on.
Check to see if the compressor clutch pulls in when you switch thre aircon on.
Alright, I replaced the fuse - to no avail. The compressor clutch isn't moving when I press the button. Do you think this might be a problem with whatever relay/fuse controls the lights behind the AC/heat controls, and the a/c switch itself? I'm new to this, so let me know if there's anything else you think it might be. Thanks!
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Brianmoooore
- E30 Zone Team Member
- Posts: 49358
- Joined: Mon Jan 10, 2005 11:00 pm
Check, (with a 12V lamp), that 12V appears at pin 2 (black/purple) of the aircon switch when it's switched on. This power should also appear at the other end of the wire, pin 3 of the evap temp regulator module.
Then check for power at the black/white wire at the high pressure switch, then at the black/yellow on the same switch
Finally, check at the black/red wire at the low pressure switch.
Then check for power at the black/white wire at the high pressure switch, then at the black/yellow on the same switch
Finally, check at the black/red wire at the low pressure switch.