The A/C in my 97' Tahoe won't turn on till about 15mins or so of driving. This happens 90% of the time. I leave the A/C switch in the on position and it starts to cool once I've driven for about 15 mins. Onces it starts, it's fine, I can cut it off and then back on. I can even turn off the engine for about 30 mins and it will still work. This has got me stumped. I had the A/C system serviced/recharged about 1 year ago, 2 months later this started happening. Any input would be appreciated.

thanks.

I would start by looking at the pressure cycling switch. This switch turns the compressor on when there is enough r134a in the accumulator. It turns the compressor off when the pressure drops below a certain pressure.

Remove the electrical connection to the switch (which is on the accumulator - a silver cylinder near the passenger firewall). Jumper the two wires in the harness. The compressor should turn on (engine running, a/c turned on).

The fact that it starts to work after 15 mins means that you should not be low on r134a. The good news is the switch can be replaced without evacuating the system. Just remove the old one and install the new one.

If the compressor does not turn on when the pressure cycling switch is jumpered, then you make have a bad clutch on the compressor.

//2000CAYukon

2000CAYukon,
Thanks for the input. I'll try your advise this weekend. Much appreciated!

I would start by looking at the pressure cycling switch. This switch turns the compressor on when there is enough r134a in the accumulator. It turns the compressor off when the pressure drops below a certain pressure.

Remove the electrical connection to the switch (which is on the accumulator - a silver cylinder near the passenger firewall). Jumper the two wires in the harness. The compressor should turn on (engine running, a/c turned on).

The fact that it starts to work after 15 mins means that you should not be low on r134a. The good news is the switch can be replaced without evacuating the system. Just remove the old one and install the new one.

If the compressor does not turn on when the pressure cycling switch is jumpered, then you make have a bad clutch on the compressor.

//2000CAYukon

The problem was the wire connection @ the pressure cycling swithch. The second I touched the connector, the compressor turned on. I went ahead a just put on the new switch since I already bought it. Works great now. Thanks for your input Yukon!

The problem was the wire connection @ the pressure cycling swithch. The second I touched the connector, the compressor turned on. I went ahead a just put on the new switch since I already bought it. Works great now. Thanks for your input Yukon!

Glad it was something easy to fix!

//2000CAYukon