Quote Originally Posted by justinc View Post
OK, I have the need for help here, testing the D2a heater blower speed transistor. The above symptoms are exactly the same, but is there a definate way I can test it without buying one (at a reasonably high price) first?

Will a simple continuity test across the transistor help????
Any typical values I should be seeing?

Thanks in aticipation,

JC
Assuming that you have the Denso system (A lcd screen with push buttons, not rotary switches)
and..... it has a power transistor for fan speed control. (some early, early d2s had a resistor block with fuse)
If your d2 has a resistor block there will be an internal fuse.

O........K.....
The transistor will be marked as "G109" and the connector marked as "C858", hidden behind the glove box.

Four wires to it, on connector C858
* Black, pin 2
* Black /Orange pin 1
* Green pin 3
* Purple/ Green pin 4

Remove unit and test unit with................

A multimeter on low ohms or diode test.

between pin 1 and 3 in one direction should be high resistance, in other direction should be low resistance. (continuity).

between pins 3 and 2 in one direction should be high resistance, in other direction should be low resistance.

Between pins 4 and 1 should be a high resistance both ways.

I have not specified the resistance values because I don't know what transistor type it is, or the collector resistor value.

However..... if you do not get the high/low values where required, its a fair bet that the device has had a meltdown.

If so, pull it apart and check the transistor numbers.
I have a suspicion that it may be a 2N3055 or similar.....common as dirt and cheap too.
You may be able to save a dollar by fitting a new transistor.

Reference: Rave wiring diagram 38:2 and workshop manual 82:12