rfunk
Well-known member
OK, I'll chime in. Had this kind of issue with automotive. Turned the instrument dimmer one way, guages went up, and high beam indicator came on (with low beams). Turned it the other way, guages went down, and high beam indicator was on with high beams. The problem is that the ground wire is the ground for another load as well (probably the other headlight), but that the ground connection is bad. So, when disconnecting the power wire, and grounding that terminal, the power goes through the first load normally, along the ground wire to the second load, and out through the temporarily grounded power terminal for this load (headlight). Because the headlight is only seeing half of the voltage, it will only be half as bright. Yup, the ground is the issue. As has been recommended, an extra ground is a good idea. Never hurt anything except the feelings of the "correct police". WILL solve the problem. The "correct police" can go and . . .