Please help with AC....

[BOP4ever]

Ok I purchased this car was told the AC needed a recharge or r134 conversion.. believed the guy.... ( maybe I was dumb )

Ok I have done conversions on AC so no problem I'll vac it out find the leak and charge it up... I put the fittings on and the gauges indicate 80-90 psi.... mmm
That should be enough for the compressor to start anyway right... IS in all the others I've delt with anyway....

Ok there is a 3 pin pressure switch low pressure cut out maybe or a combo high / low switch ? On the line behind the compressor.. any Idea what the wires are for.. I need a schematic for sure... I also found a under-hood layout thing on another GN site and found the AC relay.. I felt of those and it seems one of them is cycling on and off... felt like the fuel up relay !!! Another problem maybe ? Its dark so I'm gonna call it over for now. I hope to make some progress tomorrow !!



Anyway... Any help would be greatly appreciated !!

 

[BOP4ever]

Update... I could not quit...so I went out and did some more looking. It was the AC relay that was pulsing. I unplugged it and it went away. I then plugged it back up and unplugged the low pressure switch on the dryer. it stopped chattering. I then jumped the plug and WALLA the compressor kicked in and the gauges went to 150 over 12... IT's low on Gas that's a fact. I tapped on the switch with my pocket knife and pulled it back up. The system started working right just short cycling due to the low charge. I still have a problem with the blower HIgh speed it does not run with the switch in the high position. with the car off and key on I do not hear the relay pick up so either it's not getting the signal or the relay is bad. I did not have a meter handy to go further and still need a schematic of the circuit really.

I wonder though should I top if off with R12 I have 5 or 6 cans still in storage.... and see how it does or convert it to R134 and do the leak check etc.....
It has been 2 years since it was charged and is still holding... 90 psi with the system off.
I wonder if it would make the year and if 1 can would fill it up....?
I hate to pay the stupid AC place 200 bucks to service the AC right now... Kinda tight on cash after buying the car etc... I was all set to convert it, but if its just a little low it is tempting to keep it R12 due to the better cooling I am told I would have.. Although everything I have converted so far has done fine with R134....What do Y'all think ?

 

[TR Custom Parts]

If you have the R12 handy, give it a shot. What do you have to lose?

 

[TurboBuRick]

If you have the R12 handy, give it a shot. What do you have to lose?

I second that, If you have r12, use it. It will give colder air than 134 a in a r12 system.
The high speed fan is probably the black plug tucked down by the accumulator and pass. side fender. A real common thing in these Buick's.

 

[BOP4ever]

On the passenger fender there are 2 realys on the rail with a drip cover one is the fuel pump the other the AC relay. There is another thing with a vacuum line attached that is some kind of switch. What is that ?


Is that the high speed relay for the cooling fan ?

I plan to hit it with some R12 this evening and order a shot of that stop leak stuff to maybe seal whatever small leak may be in the system.

I need a shop manual that is a fact !

 

[Tony Shoaff]

A/c

Unplug the 2 pin connector on the passenger side that plugs into the reciever drier. Use a jumper wire to connect the two sides of the black plug . The compressor will run then and ck the psi's on the gauges.If it still will not engage the comp. there is other issues. At idle with a fan blowing through the radiator low side psi around 35 and should not drop past 30 at 2500rpm.
Hopefully that helps get the compressor running.

 

[TurboBuRick]

On the passenger fender there are 2 realys on the rail with a drip cover one is the fuel pump the other the AC relay. There is another thing with a vacuum line attached that is some kind of switch. What is that ?


Is that the high speed relay for the cooling fan ?

Thats the map sensor for your boost gauge.

Look down in that area with a light. There is a black plug down there. Between the ac box and the fender. Its not attatched to the fender, its just laying there. Find that plug and you will get your high speed fan.

 

[BOP4ever]

Thats the map sensor for your boost gauge.

Look down in that area with a light. There is a black plug down there. Between the ac box and the fender. Its not attatched to the fender, its just laying there. Find that plug and you will get your high speed fan.

I found the relay for the blower it is bolted to the evap case. Is this what your talking about or is there a relay for the rad cooling fan to speed it up as well ?

 

[TurboBuRick]

I found the relay for the blower it is bolted to the evap case. Is this what your talking about or is there a relay for the rad cooling fan to speed it up as well ?

The radiator fan relays are on the other side. (drivers side)
Not the relay, look down below to the left for a black plug. High speed is direct. No relay. What happens is that plug gets overheated and melt the plastic.

 

[BOP4ever]

Well I have no luck....
I used 2 1/2 cans of the vintage R12... 1 can was lost due to the crappy tap I purchased from autozone... blew out everywhere when I was attaching the thing to the can... had to throw it out of the shop....

Anyway ... Got it charged 99 degrees out today and it was blowing about 57 degree air from the center vent... next problem... High speed on the fan was a bad relay 10 bucks at autozone and that was good... Then it quit cooling .... got home checked and it was the dang low pressure switch again !!!

Gages say 240 high side about 40 low side.... no problems there... jumped plug and drove car everything worked great.

Next problem...
What to do about the dang pressure switch... IF I pull it it will vent the system... if I leave it out and loose charge I'll loose the compressor....what to do, what to do... Wondering if I could do a hot swap use a glove and screw the new on in with it blowing freon... ugly way to do it. The only other option would be pay the A-holes at the autoshop to evac, collect the freon and change it and recharge.... I hate having those guys touch my cars.... bad expereinces... May not have much choice though...


It's cool right now though LOL.....

 

[aminga]

Well I have no luck....
I used 2 1/2 cans of the vintage R12... 1 can was lost due to the crappy tap I purchased from autozone... blew out everywhere when I was attaching the thing to the can... had to throw it out of the shop....

Anyway ... Got it charged 99 degrees out today and it was blowing about 57 degree air from the center vent... next problem... High speed on the fan was a bad relay 10 bucks at autozone and that was good... Then it quit cooling .... got home checked and it was the dang low pressure switch again !!!

Gages say 240 high side about 40 low side.... no problems there... jumped plug and drove car everything worked great.

Next problem...
What to do about the dang pressure switch... IF I pull it it will vent the system... if I leave it out and loose charge I'll loose the compressor....what to do, what to do... Wondering if I could do a hot swap use a glove and screw the new on in with it blowing freon... ugly way to do it. The only other option would be pay the A-holes at the autoshop to evac, collect the freon and change it and recharge.... I hate having those guys touch my cars.... bad expereinces... May not have much choice though...


It's cool right now though LOL.....

The low pressure switch on the receiver dryer has a shrader valve on it. You can unscrew that without venting the system. High side on the compressor is another matter.

 

[BOP4ever]

Wow that would be too easy !!! Are you Sure ?
It looks just like the one on my 77 TA and it does not have that arrangement.

This one is screwed into the side of the accumulator / Dryer...

Please don't pull my leg on this guys...

 

[Roc87]

There is a schrader, just unscrew the sensor as fast as you can so you'll only lose a minimal amount.

 

[BOP4ever]

There is a schrader, just unscrew the sensor as fast as you can so you'll only lose a minimal amount.

Just to clarify, you say there is a schrader valve. If that is case why would I loose any.... Just wanted to make sure there wasn't an " not " missing in your post.
Or are you just talking about as the sensor first screws in and opens the valve it will loose some.

THanks

 

[Tony Shoaff]

Low Psi valve

You can unscrew the valve quickly and should only loose a small amount. The switch has a screw in it also you can screw in or out to allow the compressor to run longer or shorter.

 

[aminga]

You can unscrew the valve quickly and should only loose a small amount. The switch has a screw in it also you can screw in or out to allow the compressor to run longer or shorter.

The screw adjusts the set point of the switch so therefore indirectly the run time of the compressor. There shouldn't be any need to mess with it.

And yes. There SHOULD be a shrader valve in the low side pressure switch unless someone for whatever reason removed it.

 

[BOP4ever]

Thanks guys !!! It was just as you said and the swap was cake....

AC is complete and chilling !!!

Thanks a ton !!!


I also think I got the T-top water leak fixed..part of the stripping was not glued down and it was going under it... poured a cup of water along the seam and all stayed dry !!!

Car is nice now even in the 100 degree heat this evening it was comfortable !

fast with class... startign to feel the class part just not that fast yet anyway....