Clearance light switch issues?

[grantgoold]

I have a 1984 MCI 9. Tonight while taking it back to the barn, I noticed when I switched on the clearance light switch I would get a momentary click in the dash side panel and the clearance lights dim and the motor seems to change idle speed. When I turn off the clearance lights the problem goes away.

Anybody had the same problem in the past? I do not have da book around me but was thinking bad switch or if there is a relay then perhaps that is bad. I have also turn the light dimmer switch down or up and it does not seem to solve the problem.


Let me know!

Thanks

Grant

[Len Silva]

Sounds like a short circuit in the light circuit, tripping a breaker.

[gumpy]

Yeah, that sounds like you have a dead short.

The click sounds like a circuit breaker, but you said the engine slowed down, which indicates the short is probably not tripping a breaker.


Have someone else flip the switch while you stick your head in the electrical panel and isolate where the click is coming from. This will be the first clue to tracking down the short.

craig

[grantgoold]

Guys, forgive the ignorance but would a short cause this timed intermittent sound? All the clearance lights work and the lights do not flicker when the trip occurs.

What is a dead short?

Thanks again for the responses.

Grant

[gumpy]

Guys, forgive the ignorance but would a short cause this timed intermittent sound? All the clearance lights work and the lights do not flicker when the trip occurs.

What is a dead short?

Thanks again for the responses.

Grant

What do you mean "timed intermittent sound"?  You said in the first post that you got a "momentary click in the dash side panel". 


A momentary click is a circuit breaker or possibly a relay.  If it's a circuit breaker, it should reset and then re-trip (if you have a short causing it to trip in the first place).

If it's a relay, it could be normal, but it could also be feeding a short which is causing a voltage drop which causes the regulator to kick up the alternator output and drag down the engine.

A dead short is a hot wire which is touching ground.

Also, how do you know the clearance lights dim, if you are turning them on with the clearance light switch?  Do you also have your headlights on?

[NJT 5573]

Grant,

If you don't find a hot wire to one of the lights grounding out, check all the lenses for water. Its going to be hard on the electrical until you sort this one out, so don't let it go.