Climate control (and tape deck) exhibiting momentary loss of power

[wocketpatch]

Greetings, I have a 97 Park Avenue that is working fine more-or-less except that the climate control unit keeps losing power -- it goes dark for a fraction of a second and everything resets. This becomes particularly annoying because even if I turn everything to OFF, when it resets it goes back to the default of AUTO at 75° which causes the fan to kick in and blow heat. Sometimes it happens every few minutes, other times every ten-fifteen seconds, the fan starting up and then losing power. It doesn't seem to correlate with going over bumps or anything like that, it happens even with the car turned on but the engine not started.

So the climate control unit is just blitzing in and out, driving me nuts. The car has almost 200k miles so I'm hoping it's just some kind of relay that needs replacing, and not some incredibly expensive dash wiring harness. But, I'm not sure where to start. Any suggestions appreciated! Thank you!

 

[ryenie]

What happens if you don't turn it off when it starts to calibrate itself (that is what I'm thinking it is doing when it is blitzing out)? If you let it complete doing what its doing it may quit doing it. It may have to do it a few times and it takes about 10 minutes to complete, also have you checked the connections to the A\C control unit, those are the cheapest and first things i would check. It could be bad solder joints in the A\C unit, which apparently seem to pretty common. (I've only run into this one time, and it was last week, been working on cars 20+ years, just lucky i guess?) But that would be the next thing to check I think.

 

[wocketpatch]

Well we drove the car pretty sparingly for a while (had a kid last year and mostly only drove the other car while we weren't both working) but now we're back driving the car and this annoying thing has started up again -- but we did notice another clue that could potentially be helpful: It seems to happen more (or at least sooner) when it's hot. During the day when it's hot out it starts doing it within a few minutes of driving. At night when it's cooler we can usually make it to near-by destinations before it happens at all, though once it starts happening, it doesn't really go away. Happens every 30-60 seconds. It seems like once the engine is heated up, this behavior starts, and of course it heats up a lot faster on a hot day. It doesn't, however, seem to make any difference what settings I adjust on the climate control -- I usually just turn it fully Off.

 

[SD73]

That is kind of an odd problem. I've had issues with one item or another causing those sorts of things and had it be a relay going bad, or a AC control head. I think in your case since it's affecting two items that are probably one the same circuit I'd start working my way back from what is hopefully a common fuse they share. Maybe pull it if it's either a fuse or relay and check all the connectors to make sure they're tight. Replace it too if you can and even bend some of the female slots to make them tighter. I've even put some dielectric grease on those too. If that doesn't do it then you'll have to keep working downstream from the fuse location in search of a cracked wire or loose ground that the two items share. Finding a wiring diagram at that point will be a big help.

 

[txbarney]

You may have just a bad connection.........20 year old car, the connector my have contamination. If you can remove the unit, spray the contacts with contact cleaner and plug and unplug the connection a couple of times, that may solve the problem. Otherwise you may have a intermittent solder joint that is opening when the components heats up.