I've got a radiator cooling fan from an '01-'03 Volvo. I want to use it in an old Buick. The volvo fan has a speed controller mounted on it, but I don't know how it actually works - if it's a simple 12 signal, or a 5V square-wave, or what.
I've got the official Volvo wiring diagram (below), which matches up externally with the actual fan wiring I have. Red (A:1) power and Black
(A:2) ground leads going into the controller box (4/71), as well as a Violet signal wire (B:1) that comes from the ECM (either the ME7 or the Denso version depending on the car, but not both) Coming out of the controller box, straight to the fan motor are a White power (W) lead and a Black ground (CB) lead.
The ECM uses signals from various temp sensors (7/16 and 7/8), then tells the controller (4/71) what to do with the fan (6/29).
If I'm reading the schematic correctly, inside the controller (4/71) there's a resistor and transistors, and the idea is that the transistors are used to switch between three positions: Off, Low (via the resistor), and High.
My problem is that I can't figure out what kind of signal Volvo is passing through the signal wire to tell the controller what to do.
Any ideas on how I can control my fan speed?
I've got the official Volvo wiring diagram (below), which matches up externally with the actual fan wiring I have. Red (A:1) power and Black
(A:2) ground leads going into the controller box (4/71), as well as a Violet signal wire (B:1) that comes from the ECM (either the ME7 or the Denso version depending on the car, but not both) Coming out of the controller box, straight to the fan motor are a White power (W) lead and a Black ground (CB) lead.
The ECM uses signals from various temp sensors (7/16 and 7/8), then tells the controller (4/71) what to do with the fan (6/29).
If I'm reading the schematic correctly, inside the controller (4/71) there's a resistor and transistors, and the idea is that the transistors are used to switch between three positions: Off, Low (via the resistor), and High.
My problem is that I can't figure out what kind of signal Volvo is passing through the signal wire to tell the controller what to do.
Any ideas on how I can control my fan speed?