Another headlight question

[Adam Hicklin]

I replaced the headlight switch, which hasn't worked since I bought the coach.  Side note-wasn't as difficult as I thought it would be.  New switch was $32 at O'reilly.  Side side note- I've never driven the coach at night.  Anyway, pull the switch and parking/running lights come on but no headlights. (Yes I pulled it all the way out) Step on the high beam foot switch and the high beams come on (if the outer most lights are the high beams) but no low  beams (the inner most lights). Where do I even start, great Beaver gurus?

[Steve Huber Co-Admin]

Adam,
There are a number of possibilities. First locate TB1 pins 4 &5 (Low & High beam respectively) in the electrical bay. Using a voltmeter or light probe see if you have voltage on the low beam terminal (TB1-4) when you select the low beams. If you do, the problem is between TB1-4 and the low beam bulbs. I'd look for a bad connection.
If you don't have any voltage on TB1-4, then you need to determine if your coach has the headlight fix mod installed. Trace the wire from TB1-4  to see if there is a relay attached to it. If so, your coach has the headlight fix. I'd first suspect the relay attached to the Low Beam. Either replace the relay or check to see if you have voltage on pin 86 of the relay. If you do have voltage on pin 86 and none on pin 87, it's almost certainly a bad relay. You can get a replacement at any auto parts store. There is an outside possibility that you've lost 12v or ground to the relay. Pin 30 should have 12v all the time and pin 85 should be connected to ground.
If no relay is attached to TB1 pin 4 you have a stock system. Check to see if you have voltage on TB1-4 when low beam is selected. If yes, there is an open between TB1-4 and the headlights, probably a bad connection. If there is no voltage I'd suspect the dimmer switch as it switches 12v to either the Hi or Low beam TB1 terminals 4 & 5. If your coach is wired like mine you need to have the ignition on to get headlight voltage.
Steve

[Adam Hicklin]

Thanks Steve.  I'll do those checks first thing in the morning.

[Jerry Emert]

Adam, no expert by any stretch of the imagination but aren't the outside lights usually low beams on cars?  Inside lights high beams?  Would that change on a motor home?  Just curious.  I replaced the headlight switch on a 1969 Javelin once and it was about 8 inches long with 20 or so soldered connections on it.  I hope yours was easier than that!
Jerry

[Mike Groves]

Adam,

Jerry might be right, so in effect, your foot switch is alternating, high low, etc., and your high beams are not coming on.  When I bought my coach, I had the same issue, although I am not sure if it pre-existed the shop's installation of my HID lights which I had done during my initial service of the coach. 

At any rate, the symptom was, after installing the 4 HID (High Intensity Discharge) lights, I could get the low beams, but pressing again, couldn't get the high beams.  The shop sent a guy out, because I was a little upset at dropping about $600 (including lights and installation) and then not have full use of the lights. 

HE REPLACED THE FLOOR SWITCH, and bingo good to go!  I suspect you might have the same issue, especially if it feels a little funny (less positive) when you press it.

Hope that helps,
Mike

[Joel Weiss]

My headlights won't come on unless the engine is running.  If it isn't all that lights are the running and parking lights.  The OP didn't say if he had his engine on or not.

[Marty and Suzie Schenck]

Try turn the ignition switch on. That's the way mine work. Ignition not on, park lights and marker lights work, ignition on, they all work. No, my engine does not need to be running. Marty

[Adam Hicklin]

I did not have the key on, or engine running.  I'll certainly try that first.  As far as which position the high beam and low beam lights are in, with only one set working, I have no idea. Jerry's thought makes sense and if that is accurate it means that the low beams work, but when I step on the high beam switch, everything goes out. 

[Joel Weiss]

I should have been more precise in my post; my lights will turn on with the key in the ON position; the engine doesn't have to actually be running.

[Adam Hicklin]

This is what I found out today.  First, it looks like Jerry was correct in that the outer most lights are the low beam.  They are on with the switch, with power detected at TB1-4.  But, when I step on the high beam foot switch, the low beams go out and the high beams do not come on.  No voltage detected on either TB1-4 or TB1-5.  Am I correct to assume the problem is a bad foot switch?  All other light (running lights, dash lights) stay on and are unaffected.  I haven't been able to get under there and find the foot switch connections.  It does not appear that my coach has the headlight mod, but I do want to do it once I get this figured out. 

[Mike Groves]

Adam,

That's still my guess.  How does the switch feel?  Should work easily, whereas mine didn't.  Now the new one works very easily.  I think at this point you've probably done all the wiring testing you can do, so unless you check the leads to the lights themselves, then its probably time to check the switch.  Wish I knew how difficult the job was.  I know it didn't take the guy long to do mine, maybe 5 minutes.

Mike

[Steve Huber Co-Admin]

Adam,
Dimmer switch is probably culprit. Only other possibility (but not likely) is a bad connection between dimmer switch and TB1.
Steve

[Adam Hicklin]

I'm hoping for the 5 minute job Mike.  It does feel rough when pressed.  Certainly not smooth.  One of the jobs for today.  I'll let you know. 

[Mike Groves]

Adam,

The tech that did mine did have to trim out some carpet, but you really can notice it in that area anyway.  I think he just had to pull a few loops to get better access to it. 

Mike

[Adam Hicklin]

Mike, I wish I would have seen your last post before I started.  I spent about 30 minutes looking for it underneath, thinking it would protrude through the floor and connect from underneath.  Nope.  Once I figured out it was flush mounted I pulled up the carpet and had just enough slack in the carpet to take out the two screws holding it down.  $13 and a little time and everything works, including the little blue high beam dash indicator light.  While pulling up the carpet I did find evidence of a past leak in that area, probably from the windshield.  There was some corrosion on the dimmer switch which is probably why it failed in the first place.  Well done guys and thanks for your help!