[Marksman]

Hey everyone! Working on an 07 titan. Trying to diagnose why there is no power to the AC compressor, and see what a bunch of fault codes are resulting from.

AC hasn't worked for 2 years due to this issue. The system is fully charged, but there is no power getting to the compressor. When jumping directly to the compressor, the clutch engages and it blows ice cubes.

The HVAC fuse, as well as the compressor fuse are fine. There is 12v to the under hood compressor fuse. AC light illuminates when you press the button on the dash, if it means anything.

I unplugged what I assume is just the high side pressure switch in front of the condenser. I only have 5 volts to one of the three pins. I presume the pins are supposed to be 12v power, compressor power and ground. I jumped 12v to each of the pins, but the clutch did not engage. I couldn't find a low side pressure switch, which I think it should have.

I removed the air filter lid to access the compressor easier, and also unplugged the airflow sensor. Since I ran it when it was removed, it triggered the check engine light. I plugged my scanner in, and found a bunch of fault codes:

-P0118
-P0113
-P0451
-P0183
-P2122
-P2138
-P0643
-P0102

The cruise control also does not work.

Does anyone have any advice? I'm thinking all of these codes, the AC issue and the cruise issue might all be related.

Thanks!

 

[Pickle-Smooch]

Hey everyone! Working on an 07 titan. Trying to diagnose why there is no power to the AC compressor, and see what a bunch of fault codes are resulting from.

AC hasn't worked for 2 years due to this issue. The system is fully charged, but there is no power getting to the compressor. When jumping directly to the compressor, the clutch engages and it blows ice cubes.

The HVAC fuse, as well as the compressor fuse are fine. There is 12v to the under hood compressor fuse. AC light illuminates when you press the button on the dash, if it means anything.

I unplugged what I assume is just the high side pressure switch in front of the condenser. I only have 5 volts to one of the three pins. I presume the pins are supposed to be 12v power, compressor power and ground. I jumped 12v to each of the pins, but the clutch did not engage. I couldn't find a low side pressure switch, which I think it should have.

I removed the air filter lid to access the compressor easier, and also unplugged the airflow sensor. Since I ran it when it was removed, it triggered the check engine light. I plugged my scanner in, and found a bunch of fault codes:

-P0118
-P0113
-P0451
-P0183
-P2122
-P2138
-P0643
-P0102

The cruise control also does not work.

Does anyone have any advice? I'm thinking all of these codes, the AC issue and the cruise issue might all be related.

Thanks!

Check out the link below, it should offer some insight into what codes you are throwing.

Factory Service Manuals - NICO Club

 

[Bruisermac]

5 v dc is very common voltage for sensor and transducer operation. Perhaps you need to check to see if there is a cooling or heat relay that is not functioning....i dont have the wiring diagram. sorry. Also are you for sure certain it has a full charge?

 

[Marksman]

Thanks for the replies.

Pickle, thanks for the link to the FSM. Ive already researched what the codes are, and I guess I should've included that info.

Bruiser, I am 100% sure it is completely charged. I've never seen another pressure switch with only 5v, but i suppose it's possible. I looked forever and could not find any relays pertaining to the AC compressor. Just ones for the blower, which works fine.

 

[Bruisermac]

its a transducer not a pressure switch...it tells the cpu more info than just a on/off signal. coupled with the ambient air temp sensor the computer will monitor and adjust accordingly.