Tn75s air conditioning relay

[jammer48]

I am trying to bypass the clutch relay on the TN75S but I can't find the relay specific to the clutch on the compressor so I can activate it to recharge a completely drained system. Anyone know where it is located or how can I activate the compressor clutch since it has no freon in the system?

 

[Jerry/MT]

If it's anything like my NH TD95D, it's located on the evaporator which is above the headliner in the cab. I just had it replaced.

 

[nyone]

Never needed to located the compressor relay for a completely drained system. Did it drain out by its self? If so just add refridgerant until it kicks on. If you opened the system you should pull a vacuum or the system wont work properly.

 

[jammer48]

ok so i did pull a vacuum and it has a slow leak. I have now pulled the headliner after i put some dye in the system and I can't find the leak to save my life. I know it's a slow leak. I put two can's in about 18oz's and got the low side up to about 29psi put still no cool air. The High side was up to about the same pressure. I should have at least 150psi on the high side. I'm thinking the pressure switch/relay/valve might be stuck or at least the problem..... the compressor and clutch are working cause both cans got cool to the touch. It won't take anymore freon so I'm not sure what to do next.

 

[LouNY]

With 2 cans added in the low pressure switch should have made and ran the compressor. If you added two cans and had 29 psi on both the low and high side the compressor had never kicked on. It just equalized in the system. The cans will get cold anytime you dispense gas from the can as the liquid is vaporizing and cooling the can.

 

[Harry in Ky]

You claim the clutch and compressor are working, but your results don't confirm that. No matter how much refrigerant you add, if the high and low sides read the same pressure, you have an expansion valve problem (for openers). No offense intended, but as I see it you're in over your head on this one. No doubt there will be some well meaning suggestions coming, but you'd be better off calling in some qualified help. You already know you need help finding a leak. No one out here can do that for you.

 

[nyone]

Is the compressor turning?

 

[nyone]

No offense intended, but as I see it you're in over your head on this one.

Everyone that's willing to learn or do things them self is in over there head at some point. It's how you get out of it. If your going to smack every project with your check book you will never learn anything.

OP AC in this and vehicles arnt very hard to work on. We just need a few key questions awnsered.

 

[jammer48]

You claim the clutch and compressor are working, but your results don't confirm that. No matter how much refrigerant you add, if the high and low sides read the same pressure, you have an expansion valve problem (for openers). No offense intended, but as I see it you're in over your head on this one. No doubt there will be some well meaning suggestions coming, but you'd be better off calling in some qualified help. You already know you need help finding a leak. No one out here can do that for you.

Harry we all have to learn someway. And yes I suspected the expansion valve as well.

 

[jammer48]

Everyone that's willing to learn or do things them self is in over there head at some point. It's how you get out of it. If your going to smack every project with your check book you will never learn anything.

OP AC in this and vehicles arnt very hard to work on. We just need a few key questions awnsered.

Thank you!