I have external regulated about four 92-93 trucks because they started having charging/crank sensor issues. All trucks had check engine light on prior to the change, and I really didn't care.

So today, I changed a buddy's 93 over. He was having intermittent charging issues. He changed battery, alternator, etc. I told him it was most likely the PCM regulator part since he didn't have a check engine light and everything else seemed to work.

Charging system worked fine after the change. About 10 miles down the road while taking it back to him, the check engine light comes on. Dang it, and it's throwing a charge code.

My question I guess is, is there any way to fool it and make the check engine light go out???

I'm half tempted to hook up the external regulator and the PCM in parallel so they're both working. Or is that a no-no???