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Andy
Andy, Truck Diagnostic Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 1571
Experience:  International trucks, International, Maxxforce and Cummins engines, diagnostic, electrical, Hvac and refrigeration repairs
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I have a 2006 peterbilt 335. The air conditioning is not

Customer Question

I have a 2006 peterbilt 335. The air conditioning is not working however the prssures are good. It is obviously an electrical issue as there is no 12 volt signal being sent to the compressor. I would like to try obtain a wiring diagram so I can figure out how the 12 volt signal flows.
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  Andy replied 1 year ago.

Hi my name is ***** ***** I would like to try and help if I can. I need the full vin number please?

Customer: replied 1 year ago.

2NPLLZOX46M653179

Customer: replied 1 year ago.

2NPLLZOX46M653179 PB335

Expert:  Andy replied 1 year ago.

Thanks for the info!

Expert:  Andy replied 1 year ago.

Here is your diagram ! I enlarged it for easier viewing but in doing so , I had to split it into 2 halves . you just need to print it and put them together like a puzzle. Please do not forget to rate my service to you . Feedback is important and bonus is appreciated . Thank you !

https://www.dropbox.com/s/dkkmgajwmyyavaz/air1.png?dl=0

https://www.dropbox.com/s/hd9ue82404c8phg/air2.png?dl=0

Customer: replied 1 year ago.

OK Thanks I will let you know how it goes. For some reason I am only getting 4.2 volts at the compressor

Customer: replied 1 year ago.

OK Thanks I will let you know how it goes. For some reason I am only getting 4.2 volts at the compressor. I see a 15 amp fuse by the drivers left foot. Do you know where fuse box 4 is located? (25 amp fuse)

Expert:  Andy replied 1 year ago.

No . Unfortunately I don't ! Perhaps it's the ground side of the circuit that is dirty and needs to be cleaned up at the clutch connector( or wherever it gets its ground from . )

Customer: replied 1 year ago.

When I ground the voltmeter and pin the positive side of the connector its 4.2 volts so i'm not even using the connectors ground so it has to be something else. The wiring diagram color codes on the link you sent me seem to be different than our truck so not sure if it will work. I will check next time i'm around the truck-also there is no bunk on our truck (I'm not sure if that makes a difference)

Expert:  Andy replied 1 year ago.

Power comes from the relay according to the diagram . Have you tried swapping relays with another circuit to see iif the relay may have bad contacts inside ?

Customer: replied 1 year ago.

I will try that today. I have to find the relay. The inside cover of my fuse panel makes no mention of a ac relay so I'll look for one. This fuse box 4 has me a bit confused as I can't find another one other than the one by the drivers left foot and if there is one maybe the ac relay is in there.

Expert:  Andy replied 1 year ago.
I would imagine there to be only two panel . One inside and one outside .
Customer: replied 1 year ago.

Can you see if there is another wiring diagram option? I looked today and it's significantly different-different colors,wires routed differently, no bunk etc

Expert:  Andy replied 1 year ago.
I tried using your vin number but for some reason , the system wouldn't take it so I had to enter the info manually . I did not see any other diagrams in ther other than the sleeper hvac .
Customer: replied 1 year ago.
Ok thx. I may have to take it to the shopthen as it's almost possible to track the wires down when the colors don't match the diagram
Expert:  Andy replied 1 year ago.

I will have another look and see ! Can you tell me if it is a bergstrom system or a Behr system ? Are there any markings ?

Customer: replied 1 year ago.
On the compressor?
Expert:  Andy replied 1 year ago.

No on the hvac system anywhere on the firewall !

Expert:  Andy replied 1 year ago.

And you also mentionned that this is a daycab correct ? No sleeper at all ?

Customer: replied 1 year ago.

K I will look next time it's in-probably mid week. No cab

Expert:  Andy replied 1 year ago.

you mean no sleeper ?

Customer: replied 1 year ago.

Sorry yes. No sleeper

Expert:  Andy replied 1 year ago.

I had a bunch of other diagrams with different length of sleepers but only one day cab and that's what I sent