TB48 Condenser Fan Hack for high-speed.
Posted: 13 Jun 2019 13:33
As temperatures are rising worldwide, or hot periods becoming longer months per annum and hours per day, the cooling systems are not coping with these new temps.
My 4.8, which probably had it's design in 2003, or before has issues cooling the cabin when not moving in traffic, as there is not enough airflow over the condensor when fans are at low speed in the summer months here. We will have 40+C everyday for the next 4 months, just recieved a temperature warning from the fire department that it will be 47 to 50 for the next 4 days. I have instaled a winch, and front light bar with slim LED light, but on a stock bumper, which might also hamper air flow.
Anyhow from the diagram from the workshop manual below on what conditions will switch on the condensor fans to low, and to high speeds, I took the vehicle's coolant temp to 100C, and the fans switched to high speed, and this cooled the cabin.
Having the fans on high speed definitely makes a considerable difference in AC cooling, so I want to hack into the high speed relay, I think relay number 3, and have my own switch to use from the cabin. I am concerned that If I use a 12V battery signal, to the relay's input, that I might be putting too much voltage into that wire, and backfeed 12V to the ECM? Can you confirm whether I am right not to do this, or the ECM send a 12V signal anyhow?
My 4.8, which probably had it's design in 2003, or before has issues cooling the cabin when not moving in traffic, as there is not enough airflow over the condensor when fans are at low speed in the summer months here. We will have 40+C everyday for the next 4 months, just recieved a temperature warning from the fire department that it will be 47 to 50 for the next 4 days. I have instaled a winch, and front light bar with slim LED light, but on a stock bumper, which might also hamper air flow.
Anyhow from the diagram from the workshop manual below on what conditions will switch on the condensor fans to low, and to high speeds, I took the vehicle's coolant temp to 100C, and the fans switched to high speed, and this cooled the cabin.
Having the fans on high speed definitely makes a considerable difference in AC cooling, so I want to hack into the high speed relay, I think relay number 3, and have my own switch to use from the cabin. I am concerned that If I use a 12V battery signal, to the relay's input, that I might be putting too much voltage into that wire, and backfeed 12V to the ECM? Can you confirm whether I am right not to do this, or the ECM send a 12V signal anyhow?
