Who's familiar with late model AC?

[Pete Whitstone]

Hey all,

Trying to revive the AC on my 87. I was told by the PO that all it needed was a charge, but what I found was that the clutch is not getting any voltage when the AC is on. The clutch itself seems ok, when I supplied 12v from an external source, it kicked on. No cold air tho, so it appears the PO was at least partially correct.

Anyhow, when I turn on the AC at the control, I hear clicking in the fusebox. I looked for AC fuses and found 2 that were 25 amp each by symbols that looked like snowflakes - I assume these are the AC fuses, correct? They were both good.

The only thing I found in the fusebox that was mildly suspicious was a possibly missing relay. This relay is at the extreme lower left of the fusebox, in a block that is 2 wide by about 3-4 tall with relays. The relays appear to be plugged into different colored bases, and the one with the missing relay (if in fact there is supposed to be one there) is red, and as I said is at the far lower left with the fusebox hanging down.

Any clues what direction I should go? I'm ok on mechanical stuff but weak on electrical...

Thanks for any help!

Pete

 

[AngleT]

As I understand it

the clutch will not engage if the charge is low. I'm in the process of retrofitting mine from R12 to R134a. You'll have to pull all the lines and change the O-rings and flush the lines if you decide to do it. The oil in the R12 system is not compatable with R134a and needs to be flushed out. The O-rings, I've been told, are not the same either (something about swelling and getting brittle). I'm tackling the retrofit while the engine is out. I just hope I don't have any leaks after I get the engine back in. Electrical is an easier fix after the system is properly charged. That's where I would start.

 

[FRaCTioNaL]

Not to hijack the thread, but...

I figured I'd ask. My A/C doesnt even blow. I checked all relays and fuses and they all seem to be ok. Any other "easy" checks before I tear everything down???

BTW, if no one else chimes in by tomorrow I'll be back home. I'll check on the owners manual and let you know what the your missing relay does.

 

[budgetzagato]

If there is insufficient refrigerant...

You have to bypass the low pressure cutout switch on the line near the fuel filter. Just unplug the wires from the switch and plug them together, this should trick the compressor clutch to engage.

The radiator fan(s) won't necessarily run until the proper temp is reached, the temp switch is on one of the lines in the front luggage area. The temp switch clips to the line under some sticky tar-like insulation, it's not the one that's screwed in.

The heater unit fan will run on low speed whenever the A/C is selected, regardless of fan speed switch position.

About the missing relay... is the "seat belt" relay, controls the warning bell and/or the dash "seat belt" warning light. It is a standard "switching" relay, SPDT Bosch relay.