BRIGHTS cause loss of headlights!!

[mdpuff]

You are all correct. That type of switch is just a control type switch, the power for the head lights do not go through the switch but the switch controls a relay that energizes the head lights. I would suspect the relay is weak, just have to find said relay! That could be fun. If you get the number off your head light bulbs such as 9004, 9005, 9006 or H1, H4. They would draw allot less power and wouldn't have to replace the relay. Once you get a number you can search for a set of LED bulbs. I will try to find a generic bulb just to show you.
Good luck!

[Ray,IN]

Installing LED headlamps is just dodging the problem instead of solving the problem, and it will likely re-appear at a later time.
I would begin tracing the 12V positive wire at the headlamps, working backwards towards the relay, then the circuit breaker.
Your headlamp switch is very likely from the same or year earlier model of a production vehicle. You might try taking it to an automotive parts house and ask it they can match it to a make/model vehicle. An example: my headlamps are from a Ford produced vehicle, on my Winnebago. The same is true for most MH parts that are not part of the "house".

[golfpgb]

I agree with Ray. You are not correcting the real problem.

Can you hear the relay click or the circuit breaker trip. Maybe you can find it by letting it trip and reset. Listen for a slight click and maybe you can find the breaker and relay.

[bamaboy473]

Originally Posted by golfpgb

I agree with Ray. You are not correcting the real problem.

Can you hear the relay click or the circuit breaker trip. Maybe you can find it by letting it trip and reset. Listen for a slight click and maybe you can find the breaker and relay.

Good plan, but I'm the wrong man for the job because I have severe (they call it "profound") hearing loss, so even with hearing aids I can't hear a dime hitting a tile floor. Listening for something isn't in the cards; I either need a volt meter or a flame and smoke to find what's happening. Not the best way, but the only way.

It will be better to replace the bulbs (an upgrade any way we slice it), while tracing the relay and replacing any or all of them. I like to do this, and replacing anything 8 years old with new for the safety it provides is a good thing.

Relay sourcing begins tomorrow. Thanks all, and Happy New Year.

[gemini5362]

Originally Posted by bamaboy473

Good plan, but I'm the wrong man for the job because I have severe (they call it "profound") hearing loss, so even with hearing aids I can't hear a dime hitting a tile floor. Listening for something isn't in the cards; I either need a volt meter or a flame and smoke to find what's happening. Not the best way, but the only way.

It will be better to replace the bulbs (an upgrade any way we slice it), while tracing the relay and replacing any or all of them. I like to do this, and replacing anything 8 years old with new for the safety it provides is a good thing.

Relay sourcing begins tomorrow. Thanks all, and Happy New Year.

The bulbs are going to be a waste of money. Will not fix your problem. You have a short somewhere in the High beam wiring. Not going to be a weak relay either although there is a 1 or 2 per cent chance of that happening. Same 12 volt breaker controls power to both of your low and high beam lights. When on low no problem. When you switch to high beam the shorted wiring trips the breakers ( breakers do not trip instaneously like fuses do that is why the delay) the breaker takes a few seconds to cool off and reset that is why you do not have low until it does.

The first thing I would try is to unplug both the connector right at the light bulb first one side then the other, replug each side back in before testing the other one. See if the problem is there with each light disconnected. It might be something as simple as a broken wire in the bulb shorting to the case internally in the bulb. If it only happens on one side either physically swap bulbs or just go buy a new bulb and try that. ( IF you are comfortable with an ohm meter you can check for shorts in that line.) If it happens with both of them disconnected then the short is going to be before the wire is split to go to each side. Let us know what you find out when you disconnect each bulb.

[bamaboy473]

If it is likely that a relay isn't involved, then you confirm what I learned; that swapping out everything that looks like a relay didn't change anything.

What I DID learn was by removing both Left and Right thermal breakers and checking voltage to the breaker panel.

Tested at the fuse box, Left was 8.59V and Right was 11.51 on low beams, and both added about .2V for high beams.
Could that LOW voltage be triggering the breaker, or is that a different dog to chase?

I also pulled all 4 bulbs to test for continuity, and saw that ALL 4 are the same type (9007) 3 pins, which I assume are supposed to be Low beams. Could having low-beam bulbs where high beams are supposed to go cause over-voltage? If not, is it possible that having 4 of the same bulb is normal?

[gemini5362]

very interesting post. First I am intrigued by the fact that you have two thermal breakers (circuit breakers ?) If that is the case and you are losing both of your high beams the issue seems to be where the voltage comes into the circuit breakers. With the circuit breakers out you are getting one voltage on the one for the right and a higher voltage on the one for the left ?

Leave the right one thermal breaker out and hook everything back up normal. Turn on the high beams and see if they go out. After you have tried that put the right breaker back in and remove the left one. Put the lights on High beam and see if they go out. I do not know if having 4 of the same bulbs on your coach is normal or not. But assuming they have been in there the whole time and it has worked before I am going to assume that is not your problem. Yes having a low voltage could cause a ckt breaker to trip. lower voltage = higher current could equal a tripped breaker. Although I am not sure that is your problem. In the area that you found the circuit breakers there are probably some other fuses. What do they read when you check them. I would also probably check my chassis battery to see what you have for the voltage you are starting with. I would not be surprised if they are reading 11.51 volts. I think this is a good stopping place and wait until you have seen with one side disabled if the problem still occurs. Also check continuity of the bulbs all three pins to each other see if they are the same or within about 10 per cent of each other.

[Sky_Boss]

Originally Posted by bamaboy473

If it is likely that a relay isn't involved, then you confirm what I learned; that swapping out everything that looks like a relay didn't change anything.

What I DID learn was by removing both Left and Right thermal breakers and checking voltage to the breaker panel.

Tested at the fuse box, Left was 8.59V and Right was 11.51 on low beams, and both added about .2V for high beams.
Could that LOW voltage be triggering the breaker, or is that a different dog to chase?

I also pulled all 4 bulbs to test for continuity, and saw that ALL 4 are the same type (9007) 3 pins, which I assume are supposed to be Low beams. Could having low-beam bulbs where high beams are supposed to go cause over-voltage? If not, is it possible that having 4 of the same bulb is normal?

I have a Spartan Chassis and it has a Spartan Controller that controls headlights. At least until I modified things. LOL You might look into whether yours has something similar. If so, you have lots of homework to do before any change in types of headlights is attempted.

4 of the same bulbs is totally normal. The low beams have a beam shaping lens to meet DOT standards and the high beams are not so greatly shaped.

Swapping out stock lights for something different is not just plug and play in many cases. If you have sealed beams you may be able to find HID replacements that are DOT approved. That will still require some additional mods to your light system if the low beams are also your DRLs.

Keep in mind that you can't just toss in LED or HID lights but that they must meet DOT specifications and be approved for other than "off road" use. You can easily find HID upgrade kits with light bulbs and ballasts but those are illegal. While tossing in these brighter bulbs might seem easy they can not be properly adjusted to avoid blinding other drivers since their "hot spots" are not in the same place as the originals making proper adjustments impossible. Also, if you have DRLs then you run into a few other situations that have to be worked around.

This is a link to a thread where I replaced my low beams along with rewiring my headlight system to get around DRLs. It is based on my Spartan chassis but it might be of value for a couple reasons.

The first is that my low beams SUCKED! I did everything I could first to solve that problem. Nothing worked to improve them to a point I was satisfied.

The second was that I performed voltage drop testing as outlined by Daniel Stern to make sure it wasn't related to poor power. Testing voltage at the fuse only is probably misleading for the most part. You need to know voltage at the bulbs themselves.

It wasn't cheap either. I have nearly $1K wrapped up in this project but the results were outstanding. The advantage is that I now also know more about my lighting system and can more easily trouble shoot it. In effect, I have bypassed the Spartan Controller but all my cab switches work as normal. BTW...I never did find any kind of thermal fuses in my system. My light switches activate relays that provide the 12V power to my headlights. That was true before my mods and now after them too.

[bamaboy473]

Originally Posted by Sky_Boss

The second was that I performed voltage drop testing as outlined by Daniel Stern to make sure it wasn't related to poor power. Testing voltage at the fuse only is probably misleading for the most part. You need to know voltage at the bulbs themselves.

.

Good write-up I'm putting LED lighting on the shelf until I (er, we) solve this mystery. here's what I've learned so far:
* headlights power up fine. Turning the high beams ON causes both sides of low and high beams to go dark after 13 seconds, followed by them turning ON again in 6 seconds, then repeat the 13/6 drill as long as I care to watch it.
That suggests a thermostat type of breaker instead of a short or broken solder in the switch because it's so consistent, doesn't it?

* swapped out both thermal fuses for regular fuses. Even went from 15 to 20A with regulars. No change in the cycling pattern, and No fuses blew. Put the OEM fuses back in place. Test of thermal fuses proved nothing, other than suggesting that an over-voltage condition does NOT exist?? How can that be?

* per suggestion, removed one thermal fuse at a time. While respective sides went dark with fuse removed, the remaining, lighted, side continues the 13/6 cycle.
Cutting total delivered power in half had no effect on the cycling.

* swapped 4 bulbs around several times. No change in the cycling, so bulbs are all the same (good).

* removed one high beam bulb at a time and tested both sides. Removed one low beam bulb at a time, and tested both sides. What I learned was that IF there's only one bulb on a side, then that side defeats the cycling; it stays lighted. Doesn't matter whether its low or high beams. High beam cycling remains on a 13/6 pattern.
Does that suggest a voltage overload through a fuse? NOTE: I'd already done the fuse test and found nothing, or so I thought.

* The only relay found looks to be a normal type of relay, and its in the same fuse box as the thermal fuses. Swapped it with a different relay. No change.

The High beams can only operate with headlights on. One relay seems to control both headlights and high beams. There is one thermal fuse for each side of lights. Volts at the bulb plugs are all close to 12.80V.

What to try next?? Freightliner opens back up on Monday, but you guys will probably be able to figure this out before then. Let's solve this mystery

[Sky_Boss]

Originally Posted by bamaboy473

Good write-up I'm putting LED lighting on the shelf until I (er, we) solve this mystery. here's what I've learned so far:
* headlights power up fine. Turning the high beams ON causes both sides of low and high beams to go dark after 13 seconds, followed by them turning ON again in 6 seconds, then repeat the 13/6 drill as long as I care to watch it.
That suggests a thermostat type of breaker instead of a short or broken solder in the switch because it's so consistent, doesn't it?

* swapped out both thermal fuses for regular fuses. Even went from 15 to 20A with regulars. No change in the cycling pattern, and No fuses blew. Put the OEM fuses back in place. Test of thermal fuses proved nothing, other than suggesting that an over-voltage condition does NOT exist?? How can that be?

* per suggestion, removed one thermal fuse at a time. While respective sides went dark with fuse removed, the remaining, lighted, side continues the 13/6 cycle.
Cutting total delivered power in half had no effect on the cycling.

All of the above suggest to me that you have some kind of controlling processor like I have. If you have daytime running lights (DRLs) and can't find a DRL fuse, I'm even more convinced you have some kind of controller. SEE the picture in the first message on my thread.

...

The High beams can only operate with headlights on. One relay seems to control both headlights and high beams. There is one thermal fuse for each side of lights. Volts at the bulb plugs are all close to 12.80V.

Is that with the engine running or not? Sounds like a "not" but if the engine was running you should be closer to 13.9V.

What to try next?? Freightliner opens back up on Monday, but you guys will probably be able to figure this out before then. Let's solve this mystery

Good luck!

[Mekanic]

Originally Posted by gemini5362

The bulbs are going to be a waste of money. Will not fix your problem. You have a short somewhere in the High beam wiring.
....... Let us know what you find out when you disconnect each bulb.

Not necessarily true. the short could be the bulb its self. And i do agree to see what happens by disconnecting them one at a time.

Those bulb filaments can bounce around and cause a dead short in the bulb.
Stranger things have been known to happen.

[Stano]

I had the exact same problem with my 2003 Pace Arrow with the Workhorse chassis. Had the stalk replaced on the steering column. Did not solve the problem! Since I have sold the MH.

Stano

[Sky_Boss]

Originally Posted by Mekanic

Not necessarily true. the short could be the bulb its self. And i do agree to see what happens by disconnecting them one at a time.

Those bulb filaments can bounce around and cause a dead short in the bulb.
Stranger things have been known to happen.

New bulbs can fix some problems but since this happens very precisely at certain time intervals. I doubt this is related to bouncing/sagging filaments. Since the OP did disconnect and swap around bulbs I think that rules this out. But, you are correct, that weird things can happen.

I found that out after I installed my upgrades and last fall I had some weird cases where my low beam fuses blew. WOW. At first I thought it was rain related and some how moisture was getting over my custom relay sets. NOPE...that this happened when it rained was coincidental. Long story short it turned out to be one of the HIGH POWER cables leading from the ballast to the light was being pinched by the supporting structure for my front hood. That was a $350 mistake on top of the initial $1K investment. Had to order a new ballast since you can NOT splice/fix a bad cable carrying around 65,000 volts.

[muscob]

Check the ground wire on that low voltage high beam light side.