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Bruce H · 10-29-2016, 09:11 AM

I was checking out my headlights, high beam low beam etc. and one headlight was not working. I thought it was the bulb however during my investigation I found the connection to the bulb was melted. I replaced it with a new connection and the other side went out, same problem.
What could be melting these connections? I realized I was plugged in to my house 110 volts. I unplugged and no more problem.
Is this normal, shouldn't there be a switch of some sort that wouldn't allow this to happen and if not won't the same thing happen when the generator is running?
Your help will be appreciated.
Bruce H
The MH is a 2003 Scottsdale by Newmar, Workhorse chassis.

msturtz · 10-29-2016, 11:39 AM

This could be related to a "hot skin" condition. A hot skin is where there is voltage present on the RV chassis relative to ground. It is commonly caused by incorrectly wired extension cords and or power outlets. If you have a hot skin it is possible to get AC to the headlights and that can melt (read overload) the wiring. To check for this plug into power as you normally do and check for voltage between a known good ground and the RV chassis. A good source of ground is the round pin on a correctly wired outlet. Be very careful as any voltage over about 50v is very dangerous. The reason this can happen is because RVs have rubber tires that insulate them from the ground. They must be grounded through the electrical connection.

**Lt Dan** · 10-29-2016, 02:38 PM

There about a one in a million (or more) chance that your 120v circuits have anything to do with the 12v headlight. Those are fed from the chassis batteries through switches, relays, fuses and wiring. If you were getting 120v into the battery circuits, you would have a lot more problems than a melted connector.

Have you changed the headlight bulbs to a higher wattage type? The melted connector sounds like a heat problem, not a voltage issue.

Bruce H · 10-29-2016, 03:39 PM

About a year ago I changed out the headlight assembly which came with new bulbs. The headlight assembly used on this motor home are Lincoln Navigator 98-02. They were getting fogged so I replaced them however, I replaced them with lights that came from Taiwan.m Regarding the 110v I noticed it was plugged in and thought it was the problem and I have not tried to operate the headlights for any length of time since I unplugged. I wanted to get more info on the problem. I did replace one of the headlight bulbs with the old bulb that came out of my original lights.I wouldn't have thought being hooked to 110v would cause the problem but one never knows.Something definitely is frying the connection.

msturtz · 10-31-2016, 11:44 AM

If it is a hot skin condition then it won't travel through the switches etc on the DC side.

Bruce H · 10-31-2016, 03:34 PM

I really don't know what could have caused the problem. I did change the bulb on both head lights using my old bulbs thinking the bulbs that came from Taiwan were the problem. Again, I have not used them for any length of time to see if they go out. I also checked the battery voltage when the RV was plugged in to 110v and not plugged in and there was no difference regarding the battery voltage. So it appears the 110v is not the problem. I am really hoping it was defective Taiwan bulbs. If I ever find out I will repost.

msturtz · 10-31-2016, 10:18 PM

Quote:

Originally Posted by msturtz

If it is a hot skin condition then it won't travel through the switches etc on the DC side.

The reason it doesn't is because it appears on the ground side of the chassis i.e. "hot skin". Unfortunately, hot skin is a common problem not a 1 in a million problem. A hot skin condition means there is voltage between the chassis ground and earth ground. In many cases that could mean that there is also high voltage between chassis ground and chassis hot but not necessarily.

rarebear.nm · 10-31-2016, 10:44 PM

I generally agree with LtDan, that its highly improbable that its a "skin" issue. However, electrical receptacles do get wired wrong. In the computer business I've seen it plenty of times. If you have a voltmeter (multimeter) try checking voltage between the ground pin in the receptacle the RV connects to a solid earth ground, a copper water pipe or the house grounding rod. It better be zero volts. I think if you had a hot skin, you'd have massive electrical problems in the RV.

A little saying I use in my business is:
Nothing is impossible
Some things are highly improbable
And the impossible only takes longer

I expect it is the draw of the bulbs you're using exceeds the designed current capacity of the wiring harness to the headlights. Good luck with tacking this down.