I have a question

[nsb29]

My question is after getting the AC unit charge for the first time I don’t have high speed fans. I am using a new high pressure transducer to control the ECM and the fans, I can turn the fans on and off at the ECM by grounding the signal wire
They will also turn on with engine temperature. The compressor is controlled by the AC unit ?

[nsb29]

Ok let me ask this BP Auto says I have to have a Tuner set the pressure in the ECM as to when the fans turn on. Nothing was dun to the ECM shouldn’t it already have a setting in it from the donor car? The pressure transducer is from the same donor but new

[Joemomma1]

The compressor is controlled by the ac system not the pcm. View them as separate systems. The computers are typically flashed to retain only the bare minimum for the engine to function. AC, cruise control, etc. are not always included so ask whoever flashed your pcm. The switch allows the pcm to monitor and will turn the fans on when a certain pressure is reached. You'll want to use a trinary switch here. Don't get caught up on "high" speed fans. If you're running a single speed electric fan you should be alright assuming its adequately cooling now.

[1971Stepside]

I have this same set up. Still needs to be charged. Vintage Air and BP both told me to run the binary switch and not the trinary with the pressure sensor.

[nsb29]

Originally Posted by 1971Stepside

I have this same set up. Still needs to be charged. Vintage Air and BP both told me to run the binary switch and not the trinary with the pressure sensor.

Yes that is correct you run a Binary with the pressure transducer also I am running 3 relay set up on duel fans both fans come on low speed when reaching temperature high speed comes on at a higher temperature, Not sure what those temperatures are my 65 temperature gauge does not show exact degrees but both do work as they should. according to everyone I have talk to BP vintage air say Pressure transducer regulate the fans the actual air conditioner and compressor turn on separately from vintage air controls I guess I assumed that the settings for the air conditioning would have been left alone. I will have to call current performance Monday, I do appear to have a bump up in the throttle when a/c is turned on the throttle also drops a small amount when the a/c is turned of
The more I talk about it the more I am starting to think did I get a Bad transducer

[1971Stepside]

Interested to hear what you find. I am going to try to get mine charged soon

[Joemomma1]

Originally Posted by 1971Stepside

I have this same set up. Still needs to be charged. Vintage Air and BP both told me to run the binary switch and not the trinary with the pressure sensor.

Hmm. Conflicting info then. I have a BP harness but haven't asked them anything. I was talking to my AC guy who does this day in and out. Maybe his approach is different but how else would you have the PCM turn the fans on if not connected with a trinary? Fill me in please.

[1971Stepside]

I bought the pressure transducer from BP and put it inline on the high pressure side. My BP harness came with the provision to simply plug into the transducer.

[nsb29]

Originally Posted by Joemomma1

Hmm. Conflicting info then. I have a BP harness but haven't asked them anything. I was talking to my AC guy who does this day in and out. Maybe his approach is different but how else would you have the PCM turn the fans on if not connected with a trinary? Fill me in please.

I don’t know but mine came with a binary /trinary I wired it as a trinary and the a/c would not turn on the pump

[nsb29]

Forgot picture

[nsb29]

Problem solved replaced the transducer everything working exactly as it should fans came on low speed and then as the motor warmed up and the pressure increased high speed fans came on

[Joemomma1]

Excellent.