"Jasen Betts" wrote in message ...
On 2013-09-23, Guv Bob wrote:
"ehsjr" wrote in message ...
On 9/22/2013 11:43 AM, Guv Bob wrote:
"Guv Bob" wrote in message m...
"ehsjr" wrote in message ...
On 9/21/2013 7:46 PM, Guv Bob wrote:
The +12 from the LED connects to this component unfamiliar to me.

In your earlier post you talked about the check engine _bulb_

Now you mention an LED. Is the check engine light an LED rather
than a bulb? It makes a big difference.

Ed

Correction....
GE LIGHTING 74 LIGHT BULB
14 volts; 1 watt



Ok. That means the bulb draws about 71 mA and provides
about 200 ohms resistance when hot. If the schematic is
correct, then you can use a 22 ohm 1 watt resistor between
the transistor's collector and the bulb to replace the
existing resistor, if it's bad.

Ed

Thanks Ed. My problem is finding the transistor. The circuit
connects from pin 64 of the connector to CM104. I'm lost from there.
There's no way to know where it leads from there, and no schematic
showing where the base signal comes from.

The transistor may be internal to CM104

Hmm... I traced the pin-outs to the connector and labeled them. There's only one input from each component, so that seems to eliminate both the transistor and resistor that are in series with the light. Check this out...

I identified the pinouts on CM104 if that's any help....
http://imageshack.us/a/img580/2863/scfa.gif

Not Mitsubishi, but here's a typical block diagram from Toyota...
http://imageshack.us/a/img266/1418/q4rl.gif