Lights Flickering When Idling

[sdennislee]

Both the coach lights (ceiling etc...) and the head light Flicker from bright to dim as the coach idles, disconnected from shore power and generator.

Where should I start? Could this be the alternator.

2009 Safari Cheetah.

Thanks

[George Z]

I would check the cable connections to and from the batteries, especially the ground to frame. then have battery tested.

[Kablewizard]

I don't know if your coach is doing the same thing my Truck is( Dodge Diesel 2500), but on cold mornings my lights also goes dim and brighter as the truck sends voltage to warm the glow plugs for the diesel. Once the truck is warm it stops and everything is fine.

[sdennislee]

Quote:

Originally Posted by Kablewizard I don't know if your coach is doing the same thing my Truck is( Dodge Diesel 2500), but on cold mornings my lights also goes dim and brighter as the truck sends voltage to warm the glow plugs for the diesel. Once the truck is warm it stops and everything is fine.

I will let it idle longer tomorrow and check.

Right after I check all the battery connections.

[ntrsandman]

Quote:

Originally Posted by Kablewizard I don't know if your coach is doing the same thing my Truck is( Dodge Diesel 2500), but on cold mornings my lights also goes dim and brighter as the truck sends voltage to warm the glow plugs for the diesel. Once the truck is warm it stops and everything is fine.

The bright/dim on Dodge diesel trucks is normal. Dodge Cummins engines do not have glow plugs. They are true diesels. The time you wait to start the engine is to heat up the intake air heater at the intake manifold.

I agree about checking the battery(s), connections, and charging system.

[Alan_Hepburn]

Quote:

Originally Posted by ntrsandman ...Cummins engines do not have glow plugs. They are true diesels.

The presence, or absence, of glow plugs does not indicate anything about a diesel other than the way the designers chose to implement a cold start system. Some - such as Navistar's Powerstroke (built for Ford) - chose to put a glow plug into each cylinder to help heat the incoming air; others - such as Cummins - chose to put a heat grid in the intake snorkel. If I recall the venerable Detroit diesels also use glow plugs - it's hard to believe that THEY'RE not "true" diesels...

[LVJ58]

I also vote for checking battery connections and ground to chassis frame.

Good luck

[ntrsandman]

Quote:

Originally Posted by Alan_Hepburn The presence, or absence, of glow plugs does not indicate anything about a diesel other than the way the designers chose to implement a cold start system. Some - such as Navistar's Powerstroke (built for Ford) - chose to put a glow plug into each cylinder to help heat the incoming air; others - such as Cummins - chose to put a heat grid in the intake snorkel. If I recall the venerable Detroit diesels also use glow plugs - it's hard to believe that THEY'RE not "true" diesels...

Thanks for the lesson! I did not think before I wrote. I appreciate not being chastised for the remark.

[sdennislee]

Went out today and tightened every nut and bolt I could find:
All 6 batteries
Every lug in the B.I.R.D system
Every lug in the breaker box
Every nut in both fuse panels
And the chassis ground points, who ever decided on their location was off his rocker.

Ran out of time to check the main box and the inverter connections, too much stuff to move will get them tomorrow.

Didn't really find anything to be loose but the lights quit flickering.

Thanks for the suggestions and taking the time to reply.

[ntrsandman]

"Tightening" may have provided a temporary fix. Best bet is to clean all connections. May seem like a pain, but any corrosion, dirt, etc. increases the resistance for electricity to complete its path. Even connections that look good can cause problems. JMHO.

[sdennislee]

Other than the ground to chassis they looked clean. The battery connections all had fresh oxide inhibitor, now so does my 9/16" socket. I will need to take it to someone to get the ground points off and cleaned. It was all I could do to get a wrench on them.

I have some down time in Texas next week, I will pull the others off and clean.

[wa8yxm]

If your idle speed is low enough the alternator can "Drop out" (The output voltage drops below 13.6) when you go to idle.. This is normal on many vehicles.

Is it normal on yours... Alas, I do not know.

This I do know.. The alternator eats horsepower, and thus Gas, using a slightly larger pully on the alternator makes it turn slower, thus lowering the load it places on the motor.. NORMALLY this is done in "Performance" cars, (IE: Race cars) not motor homes. but hey, someone could have grabbed the wrong pulley.

It could also be an "Issue" if it is something new.

[sdennislee]

wa8yxm, I will check the alternator output at idle, I assume I can do this with my multimeter???

It is a new issue. I had just picked it up from having some service done, nothing that would have likely caused this problem. I had hoped it was just the batteries were low and would go away after being plugged in for a few days.