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1988 Sub / A/C needs help!

T

toyotajeep

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My Suburban A/C does not work. There is no power to the compressor, but there is power to the dash switch, and power out of the switch. BTW - the rear A/C does not work either. It was working fine before. Is there a relay or something? The fuse is fine.

Thanks You for your help.
 
Little more info needed. Is it the blowers not work or the clutch not kicking in? The rear A/C always has freon moving through it if the front A/C is turned on. The plumbing just Y's to the AUX unit in the back. Basicly if your going to trun the front on might as well turn the blower on for the rear.

There are two paths of power to the front blower. High comes off the block on the firewall next to the master cylinder and the low-med comes through the switch on the dash through the resistor pack on the A/C box under the hood then through the relay on the blower box.
If it's just not blowing cold then it's proably a bad clutch or low on freon. By the under hood box on one of the pipes is a pressure switch that will not cut on the compressor if it's low on freon. You can unplg it and jump it for testing. If the clutch comes on then it's low on freon.
 
That helps some. What is happening is that when I turn on the AC the lead to the compressor is not hot. It has no voltage to start the compressor. Any ideas on this?

Thanks, ROB
 
There's a low-pressure switch on the suction side of the gas circuit that will interuppt power to the compressor if the refrigerant charge is too low. It's there to prevent the compressor from self destructing in the event of a refrigerant leak. /forums/images/graemlins/cool.gif You'll usually find the switch on or near the dryer/accumulator. If you unplug the connector, then jumper the 2 wires together, you'll probably find that you now have power to the compressor. If so, then it's time for a recharge (and probably time to find the leak).
 
really, i have the problem where mine will turn on and off really quick, and then go on and off really quick again, and all it blows out is hot air, and the charge is nice and high, im stumped on mine too., /forums/images/graemlins/frown.gif
 
Sounds like yours is either overcharged or a line is plugged up somewhere. There's a high pressure cutoff switch that kills power to the clutch when the high side pressure exceeds something like 470 PSI. /forums/images/graemlins/eek.gif
 
That's what it was. I must be low on Freon. I jumpered it and everything went on, but I didn't have any cool air. Now it's time to look into Freon options.

Thanks very much for the help!

ROB
 
[ QUOTE ]
That's what it was. I must be low on Freon. I jumpered it and everything went on, but I didn't have any cool air. Now it's time to look into Freon options.

Thanks very much for the help!



ROB

[/ QUOTE ]
Well these trucks were designed for R12 and the R134 stinks in them. My 88 is converted. Does ok going down the road with the RPM's up and plenty of air flow but get stuck in traffic and it's a little disappointing. It was profesionnal converted by a reputable compnay and was done right. Problem is systems that were designed for 134 have larger condensors to make up for the loss of cooling potential between the R12 and R134.

It's a what are you going to do deal. $4 a can verses $30 a can last I heard R12 was going for. It's a huge amount of Freon it uses with the Dual Air. If the system has lost all charge you talking $150 worth of R12 at least.
 
[ QUOTE ]
I was doing some searching around as well, and came across this:

http://www.refimax.com/products/fr12.htm

Anybody know or have any experience with this stuff? It claims it can be used as a direct substitute, without conversion for the old R-12...

[/ QUOTE ]

Hmmm had not seen that one. There is another that is basicly propane. /forums/images/graemlins/crazy.gif
 
I did read on the internet that it _can_ work, but it is not legal nor safe due to the obvious explosion potential of propane in the event of a leak.
 
I converted my 87 s10 to R-134a last week.

Reasons for converting:

1) Air blew at 70* on a 90* day and clutch cycled on/off about 15 times a min.
2) I don't like other people working on my truck and I can't put R-12 into it.
3) In the next year or 2 I will be swapping in a TPI v8 and will need to change lines, compressor, and cond. Now I have all the tools to do all the AC work.

Parts:
I bought a new accumulator, orfice tube, and a conversion kit.

Process:
1) Remove old accumulator and orfice tube.
2) Flush old lines, evap, cond, and compressor with paint thinner and blow it out with compressed air.
3) Clean up paint thinner mess /forums/images/graemlins/rolleyes.gif
4) Install new parts and conversion fittings.
5) Evacuate system for 1 hour using $14 venturi vacume pump from Harbor Freight (I had to make a line to attach it). It pulled 26.5 in-Hg at 90 psi line pressure.
6) Put in POE oil that came with conversion kit.
7) Put in R-134a that came with kit along with one extra can (from what I have heard you are suposed to use 85% the weight of R-134a as you would use R-12).

It will now blow sub 50* from the vent on 90*+ days and cools off real quick. The clutch doesn't cycle on/off all the time any more.

I am happy with it for now. When I do the engine swap I might put in some propane mixed with the R-134a or might just go all propane. Propane is more efficient than R-12! I am not woried about propane in the AC system. I worry about things like Compressed Natural Gass powered motors because of the volume they use and the very high pressures they run at.
 
Butane/propane does release heat when it turns from liquid to gas, just like r12. You can get r12 in mexico but it is rummored to be spiked with butane.


Check ebay for r12. It is going for about $20
 
Whirlpool makes a product I sell to technicians at my appliance parts store in AZ. Its called r414a. It is a blend and works directly in place of r-12, you just use 20 percent less product than an equivalent charge of r-12. I sell licensed techs this for 9 dollars a can. So find a buddy who charges refrigerators and ask him for some. The sysytem DOES NOT have to be converted.
 
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