LOW AC ON MY 1989

[charlie1]

i keep getting a message on the crt that the freon may be low (r12). had it checked for leaks but none can be found sees to occur on chilly somewhat damp mornings. system is full of r12.

was going to replace low pressure switch, was told you do not have to drain freon as their is a schrader valve under it ?

ANY THOUGHTS FROM THE EXPERTS WOULD BE APPRECIATED.

CHAS

[Howard]

Just so you won't feel alone, for the past two winters my 89 does the same thing. Everything checks out OK. The warning only seems to come on if the temp. is around 50. Anything above or below that, it's OK. Howard

[Guest EDBS0]

Freon does slowly leak over time. In cooler weather it also does not expand and create the additional pressure it would on an eighty degree day. In all likelyhood you have a very slooooow leak that you can't find, might even be at clutch bearing. Chances in spring when temperatures increase in PA your low refrigerant warning may disappear. You may have also noticed marginal cooling in recent months. Likely you are down a pound or so.

Keep watching there are always a number of similar posts at this time of year.

Thanks Howard. You posted while I was composing mine, there will be others

[charlie1]

thanks folks,

2 years ago i put in a rebuilt gm conpressor. last summer i had the evaporator replaced. thought i had the problem fixed. we added dye in r12 and still cannot find a leak. guess i will just have to save my small supply of r12 i have left.

thinking about jumping lower pressure switch!

thanks

chas

[Guest Greg Ross]

It's also conceivable it's an electrical fault/ poor connector conductivity at the low pressure sensor. I've had the 'Warning Low A/C Refrigerant" happen about twice in the past six years after messing around unde the Cowl Cover at the Firewall. Last time this happened was when I was changing out the Wiper Motor and Arms. If the connector to the Low Pressure sensor is distrubed even with the Car not running/ Ignition Off" it will register. It's possibly this and to me a reminder to carry on disconnecting and applying electrical contact cleaner to all those plug Connectors I didn't get to the last time I was inspired to do some Housekeeping.

Nick Walker and I were talking about this last night, with the low voltage circuits used for signaling in many of these "On-Board" Systems, any amount of oxidation on the pins and Sockets in the multitude of Connectors on our cars can play "Havoc" with Troubleshooting, particularly intermittant problems and faults.

You can always get radical and replace all these connectors with Aviation/ Gold Plated hardware.

[Guest]

thanks i knew i would get some good advice from the experts.

funny just changed wiper motor last week!(will check things out)

what do you think of die electric grease on connector pins?

chas

[Guest EDBS0]

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[Guest]

It's hard for me to believe that GM would add cut into their profits and add something that probably won't be needed while the car is still in warranty. But I guess anything is possible.

Be absolutely certain there is a valve before you remove the switch with a charged system. Refrigerant can cause serious bodily harm.