Cadillac Owners Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
1991 Brougham I'm trying to charge my ac system
It won't go into auto
I jumped out the low pressure cut out switch
No auto
Disconnected negative terminal turned ignition on to clear codes
Hooked negative terminal back, still no auto
Any help would be appreciated
 

·
Registered
92 Fleetwood 2dr cpe - FWD, 96 Seville SLS, 02 Seville
Joined
·
1,007 Posts
What codes did you clear, they should tell you which sensors are tripped as how to proceed.

Do you have guages, what is the static pressure?

You can bypass all the controls, but likely overfill.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #3 (Edited)
I got a 48 code wich I believe is a misfire? I don't have gauges yet but it sounds like there is some pressure. If I do bypass the controls and charge it till I get 50 degrees at the outlet do you think it will work in auto?
I jumped out the low pressure cut out switch, what else is there , I don't see a high pressure switch?
 

·
Registered
1993 sedan deville
Joined
·
43 Posts
Im not a certified mechanic .So take this with a grain of salt. I had the same problem on my 93 Deville. The answers were not forth coming from any source. I did not get a clear meaning of the codes since he list is numerical and you have to assume what the preceding letter mean.
After being frustrated I began looking at the engine compartment fuse box .Low and behold on a label was the instruction for refilling.
This does not mean your car has the same instruction.My factory label was this put at least 1 lb of refrigerant in.
Disconnect the ground cable for 10 seconds. Reconnect and set the climate control to 60 degrees start your engine and fill to specification.
It worked but of course I have a leak, so fix that before you worry about refilling.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #5
The 5th line down I wrote that I disconnected the ground wire and turned on the ignition to clear codes and still no auto
Well today it didn't start with 12.7 volts
Looked at the battery 2005 May....need a new one grrr
 

·
Registered
1993 sedan deville
Joined
·
43 Posts
I noticed that line , I posted the instructions as per a 93 Deville. Maybe the pre charge before the battery disconnect is relevant . I meant no disrespect of your efforts.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #7
No offense taken I appreciate your time I thinking my battery may have something to do with it
 

·
Registered
92 Fleetwood 2dr cpe - FWD, 96 Seville SLS, 02 Seville
Joined
·
1,007 Posts
Cadillac fill procedures specify a volume / weight of Freon to add to a vacuumed system.

A std approach is to do an initial fill to a vacuumed system and that will introduce enough Freon to clear the low pressure switch. Static pressure (car off) is typically 70-90psi on both low/high.

The low pressure etc switches are typically in line on the signal wire to the ac relay. Once tripped, the relay delivers power to the coil. I believe the high pressure switch is mounted on the backside of the compressor and is wired in line with the ground leg of the coil circuit.

You can bypass all control switches by jumping the relay. If it works, then you have control / fuse problems. If not, then coil/high switch/ wiring problems.

Confirm the relay socket by testing for voltage using a known ground. You should see 12v on 2 of the socket spaces. One is the low amp control signal. The other is the high amp power to the coil. Of either is missing, then problems with control/fuses/wiring.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #9
I know that there is no 12 v to the compressor relay coil , because it's not going into auto
I assume that the only safety/limit switch is the low pressure switch is there another?
I also assume it's an on or off switch, could it be a variable pressure switch?
I'm waiting for adapter from Amazon so I can use my gauges
Also I know where a/the leak is , it's the high pressure Schrader valve when I removed the cap I could hear it ,so I'll replace that pull a vacuum and see if it holds and put new adapter on
Put some r134a in it to 70 psi and it should go into auto ......fingers crossed
 

·
Registered
92 Fleetwood 2dr cpe - FWD, 96 Seville SLS, 02 Seville
Joined
·
1,007 Posts
Car on and running, one socket of the relay should have 12v. This is the primary circuit to the coil. The relay passes this to the coil of the control circuit is completed.

The control circuit includes the low pressure switch, the dash control and interior temp switches.

You should have 1 12v at the relay socket all the time. 2nd 12v will be seen at the socket if ac is turned on and all switches are closed.

For this generation of gm cars and compressors, the high pressure swItch is typically mounted on the compressor and wired into the primary coil circuit.

If you are mIssing the first 12v, then you have a problem with fuse, ignition, wiring. If the 2nd is missing then a problem with low pressure, swItch, fuse, temp control or wiring. If both are present and the coil does not engage, then problem with coil, coil wiring, or high pressure switch.

As for the leak, you can replace the Schrader valve insert. If you want to maintain pressure (and not vacuum), you can utilize a specialize tool that mounts onto the valve and keeps pressure while removing the insert.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #11 (Edited)
Ok there must be an other switch because when I put 55 psi on it the compressor started and now everything is working.
I put 30 oz. In and spray all suspect areas with soapy water
What is the total amount of referigant it should hold?
Also the high side port is smaller than my adapters see pic I'm holding the high side and low adapter
587568

Thanks
 

·
Registered
92 Fleetwood 2dr cpe - FWD, 96 Seville SLS, 02 Seville
Joined
·
1,007 Posts
That looks the original r12 port , with an collapsed schrader valve. If converted to r134, the convertor should have installed adapters. The adapters are Sized differently for low and high. A r134 guage will "clip" onto the adapters.
 

·
Super Moderator
2010 DTS
Joined
·
87,286 Posts
Kind of hard to tell from that angle, but being a '91, and the closer I look at it, I suspect you are right. I missed that.
 

·
Registered
92 Fleetwood 2dr cpe - FWD, 96 Seville SLS, 02 Seville
Joined
·
1,007 Posts
Kind of hard to tell from that angle, but being a '91, and the closer I look at it, I suspect you are right. I missed that.
posting under the influence. . .
 
1 - 16 of 16 Posts
Top