Air Conditioner??

[dirtridinz71]

Well the 98 is the first truck to have a "working" AC system. Last week we had a few hot days and it didnt seem to blow very cold. Today I tried a recharge kit, still not much improvement but I was not sure if the compressor is working properly. Without the truck running it help good pressure but once compressor kick in it would drop and then pick back up once compressor dissengaged. Couldnt tell what pressure dropped to though as it would not stay running long enough.

Here is a video to show how compressor is working, this is with AC on high and max.

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[JAW's]

A lot of compressors will run like that or not at all if there is not enough freon in the system. (safety thing for compressor) how big was the recharge kit you used? I believe our system uses at least 2 pounds.

Also was the compressor running when you charged it. If not you have to jump the fuse so that the system is charged properly.

 

[Swaggerwagon]

It looks to be cutting off due to high pressure...probably due to a clogged orifice tube....very common GM a/c issue...

 

[dirtridinz71]

I had just tried one of the small cans, didnt want to overfill it. So the compressor needs to run full time to probperly charge system? If so can you explain more on bypassing the fuse to get it to.

 

[dirtridinz71]

It looks to be cutting off due to high pressure...probably due to a clogged orifice tube....very common GM a/c issue...

Any way to unclog tube or have to replace?

Edit: Also the recharge kit I got came with the gauge, once compressor kicked in the pressure dropped, wouldnt a clogged tube cause a pressure rise?

 

[badazzbulldog]

there is a plug on the accumulator/drier pass side firewall unplug it and jump the 2 wires with a paper clip and charge with another can of freon and keep checking to see if it gets colder,its cutting off quick due to not enuff freon in the system

 

[dirtridinz71]

there is a plug on the accumulator/drier pass side firewall unplug it and jump the 2 wires with a paper clip and charge with another can of freon and keep checking to see if it gets colder,its cutting off quick due to not enuff freon in the system

Thanks for the help, completely new to doing anything with the AC systems. Keep the good info/tips coming.

 

[badazzbulldog]

no problem

 

[JAW's]

Yes the compressor must run the entire time you are refilling the system. You can do this by what Scott said or by finding the fuse/relay in the main box under the hood And use a jumper wire.

 

[SAATR]

Any way to unclog tube or have to replace?

Edit: Also the recharge kit I got came with the gauge, once compressor kicked in the pressure dropped, wouldnt a clogged tube cause a pressure rise?

The orifice tube is located at the junction shown in the picture. Evacuate the system, open this line, and the orifice will be a plastic insert in the larger of the two tubes. Should be located under your air filter housing.

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The plug on the accumulator shown below is what you want to disconnect, and then bridge with a piece of wire or a paper clip. This will engage the compressor and allow you to charge the system without the compressor cycling (unless the high pressure switch cuts it off). You really need gauges on both the high and low pressure sides of the system to accurately gauge what the problem is, without wasting money on freon (if it is overcharged or merely clogged).

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A clogged orifice tube would cause the pressure to rise on the high side, while causing a corresponding pressure drop on the low side. If your gauge is one of the kind that is built in to a charging hose, then you are only reading low pressure, and don't have a completely accurate picture of what is happening.