SSminnow

Well guys, here is the deal. I went out and took the ground for the TST box off of the neg terminal on the battery, and ran into the truck, under the dash, and ground the box there.......and guess what??? A/C works again I hooked the gauges up, and it is now @ 65* and I am getting 25LBS on the low side before compressor shuts off to build pressure back up, and on the high side got close to 160 LBS before the compressor shut off and pressure would start to equalize and low side would rise to @ 40 LBS before the compressor turned back on and high side would drop to @ 120 LBS before the compressor would turn back on.

I know it is hard to get a good reading on pressure with temps a little cooler than the summer, but if anything, I may be a little low on freon. However, I am not going to add any until it warms up so I can get a better reading.

Also, I will keep you guys posted to see what happens tomorrow, as tonight may have been a fluke deal. If my A/C works all day tomorrow, problem has been solved. If it acts up again (hopefully not) then I will go with ya'lls diagnosis and go from there.

Seems odd though, that as soon as I swapped the ground, and started the truck up, A/C started working perfectly

I am going to talk to TST tomorrow and see what the deal is with that (IF that is/was the problem).

The only reason I was even reading my TST manual, is I am getting ready to make a road trip from Texas to Connecticut, and wanted to read up on the "Economy" setting, and I came across that little sentence:

NOTE: If you have installed a FASS or other similar pusher pump (I have the Walbro) you may get a fault code for AC clutch problem. This problem can be resolved by cutting the ring terminal off the ground wire and extending the ground to the lower edge of the dash inside the cab. In this case, do NOT ground to the battery.

Not sure why, but hopefully that was the problem. Will let you guys know tomorrow.

SSminnow

Well, maybe I will jinx myself, but my A/C has been perfect all day. That is weird about the ground wire for the TST causing that.

Diesel-Dan

We got this one more in the summer time.....but had to do with the electrical noise of the motor causing interference. Its is indeed a weird one......

SSminnow

OK, A/C still working fine, so seems to have fixed the problem. Now, I have to fix the Defrost/Floor door

SSminnow

Yep, that was what it was. A/C is working just fine (minus the defrost/floor doors) whcih Ihave begun reair work on before I left for Connecticut on Thurs. I am going to buy the parts tomorrow, and try and finish up tomorrow or Tues. Going to replace the Fin Temp Sensor while I am in there also.

Helmutt

Is 50 pounds pressure too much on a 100 degree day (ambient temperature)?
That's what mine was after the recharge. My AC is blowing nice and cold but I don't want to have it overcharged.

79warlock

Is that low side pressure with the system running, or is that pressure with it off? It should be over 100psi with out the system running at 100deg ambient.

TonyB

I'll take the 70F days any day of the week! We've been suffering through the 'teens AGAIN this year! Back in early July we were hitting 113-115; now this weekend it's back into 113-115 AGAIN. You know what I love about AZ summers? When they're over!

Sorry about the sidetrack...we now return to your regularly scheduled program....

ram440

Upon start up with engine at ambient temperature and the ambient temp is 100 degrees I have 35 -40lbs on the low and 275lbs on the high with the engine fan engaged. After shut down the pressures equalized at 110lbs.
Is this about right? I just gave it a charge due to passenger side not as cold and don't want to over charge.
Thanks

TonyB

IIRC, that's about what mine are.

Tony

colorado bill

I would have to say it sounds like it is over charged,you mention low pressure but what is the high side at usually thats were your high pressure switch is at on the high side line.I would start over and put in the exact amount reqired and no more R-134a does not work well when over charged once high side pressure is excessive cooling is greatly reduced not like the old r-12 I do work for a cat dealer and work on alot of a-c systems have seen this problem plenty of times from guys not weighing the refridgerent and trying to guess by pressures on the gauge just not very accurate.
I would also reccomend Master Cool digital gages as they actually show the temp of both the low and high side going through.just my 2 cents good luck.

ram440

Sorry about hijacking the thread but - Thanks for letting me know mine was within normal range for Arizona 100 plus temps now. If it wasn't for my son complaining about the passenger side not being as cool I would have left it alone. Drivers side was still cold - Crazy design flaw if you ask me