On 9/22/2013 8:20 PM, 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.

I'll keep looking for a schematic. In the meantime, I'll take the suggestion to his the junk yards.



Groan. In fact, double groan. Tracing the thing out on the ECU,
if that is possible, still might not yield the fix, because the
transistor/resistor might be good. If you could trace it to the
transistor/resistor, you could use just about any NPN transistor
to replace it and add the 22 ohm resistor, but that still might
not fix the problem. And, who's to say something else won't become
defective in the disassembly/troubleshooting/repair/reassembly
activity. Grumble.

Ed