Lights Out When High Beams Are Turned On...

[southernman]

Guys, I know there are other posts out there regarding this topic, but they're old now, and I'm unsure of the relevance. Here's my issue:

Actuating the high beams results in a short and I can hear a pulsing relay or alarm "sound" coming from behind the dash.

I've been through everything I can think of and here's a list of what I've done:

New Headlight switch - same problem.

New Emergency Flasher switch - same problem.

Because my first instinct was the dimmer switch, I removed the factory dimmer switch from the harness and wired in a three-position switch so I could check the low and high beam function - before purchasing a new switch. I'm 99% sure the switch is good as noted below...

The low beams work fine. I have supply voltage from the harness connection to the dimmer switch (Pin 56 from the headlight switch, with ignition switch ON, has 12 volts).

Ignition still ON, I have connection between 56 and 56a, which turns the low beams ON, and they work properly.

When I switch to high beams, and connection between 56 and 56b, I get the dead short scenario (dash lights pulse and the wires immediately start getting warm), and I have been unable to trace this problem to a single component. The generator and OP light (both red) blink when the high beam circuit is energized.

Unplugging either, or both, headlamps and retesting - same condition.

Pulling each (and every) relay I can reach, one at a time, and retesting - same problem.

I checked to ensure there is no voltage present at 52b with the ignition switch ON (i.e. when not energized).

The wiring diagram and manual state there are no relays in the headlight circuit, but it sounds like I'm getting feedback through a relay or set of contacts elsewhere in the system, and the sound appears to be coming from behind the instrument cluster... I know I can figure this out - if I tear the dash out and run a full trace, but I was hoping that someone experienced this same problem and can offer a solution or suggestions.

Again, as noted above, I've bypassed nearly every component in the system, but when I apply power to the high beam circuit, I get the dead short. The high beam indicator light does not illuminate either, if that helps analysis.

I appreciate any feedback and experiences other may have had.

Southernman

 

[damac]

fuses?

i had a cluster that didnt light up for high beams due to broken contacts, but lights still functioned fine

[southernman]

Thanks Damac, but I've pulled and checked every fuse in the panel. I forgot to state it above, but it was the first area I checked.

Also, I've never seen a fuse survive a dead short scenario like I'm seeing with this vehicle. If I were to leave the 3 position switch in the high beam position, it would probably fry the temporary wiring I've installed for testing.

Thanks for the suggestion though and I'm hoping some others will have experienced this problem.

When I review the wiring diagram, the high beam panel light shares connections with several other relays that are NOT associated with the headlight function. The only component in the instrument panel that's tied to the head lights is the blue indicator light, triggered by the hi-beam selector switch, but every other idiot light feed is "ganged" through the instrument panel making any upstream relay a potential fault...

Everything on the input side of the switch is working fine; it's the other side (output) of the switch where I'm have the problem. The wiring diagrams tell me any relay that can trigger a light in the instrument panel (with the IGN in the ON position) could trigger a fault, and that's what makes these things such a pain in the butt to troubleshoot. Circuit 15 feeds to the instrument panel are shared by multiple devices, many of them relays, so I'm probably going to be forced to rip the dash out to find it.

Thanks again for posting.

S

[damac]

is this a new chasis for you or sudden problem on truck you have driven?

if the first i would say yank the dash no matter what because of old owners.  ive only come across one car that wasnt touched.  mostly people yanking wires to install radios.  one loose wire going somewhere bad can make something act wierd when triggered or start a fire, which i now have seen twice without blowing a fuse!!  and that wire gets too hot to touch and melting wire inukation all the way to fusebox.


does everything actually work electrically until high beams are hit?

those truck tails can have their grounds jump and do wierd stuff.

also seen wierd stuff at fusebox because they like to leak water through windshield.  also noticed more than one old relay do wierd stuff with power.

it only takes one bit of exposed wire to hit other or exposed grounded metal behind dash, i would just yank the dash now before you drive it because they rattle so much.

sorry for babbling, ive learned a daily driver gets all good parts and my dashes come off for inspection.  great time for heater core and reseal hvac box and flappers.


oh yeah and my 79 rabbits dash smoked out one night when i noticed battery wasnt charging.  for some reason all sorts of legs on board let loose, broke and were arching.  couldnt believe it i dailydrove almost a year with everything working. 

[southernman]

I've had the truck for a couple years and everything "under" it is new. I'm in the process of painting and doing the interior over the next couple months.

So, not a new chassis to me. Everything else works on the truck, except the high beams, and I need them for inspection, which is now 3 months overdue...

It does have it's fair share of "dangling" wires, but the test light reveals they are probably not the problem. I've also fixed bad grounds to the horn, etc, and other typical electrical problems, but this one has me baffled - and I actually like troubleshooting electrical issues - but I don't like "unbundling" everything to troubleshoot, if you know what I mean, but if you can't see the wires, it's pretty much the only way...

Fuse box has a little rust, but I've cleaned all the contacts and pretty much eliminated the fuse box. Besides, there are no relays in the headlight circuit that I can detect. Ignition ON; power to the HL switch is good; power to the dimmer switch is good; applying power to the high beams - dead short...

As owners of old VW's, it's the story of our lives ~{:>) Again, thanks for the suggestions.

S

[DogDiesel]

I installed zenon headlamps in my 81 Caddy pickup and my headlamps would work for a few minutes, max 10 and flicker off, but also do the same after a period.  Would last longer if cool weather than hot.

I installed relays to the headlamps, and work perfect.  Problems solved, switch and dimmer fine.

My situation is not analogous to yours, but VWs are finicky with amperage.  Circuits are designed to run about the load of the fuse, and switches also won't tolorate much more.

No clue why your high beams are over-amping, but I'd isolate the high beam circuit. 

I might run a test like...

remove the headlamp fuse, splice in a bulb at high beam connecter, hot wire to bulb, bulb ground to headlamp circuit.  If bulb burns, I'd know I have a ground, burn bright, big short.

no light... no problem.

Install a H/L relay.

Wayne

[southernman]

Wayne, thanks for the suggestion and I've given some thought to testing as you describe.

Problem is, I can disconnect either, or both, headlamps, and the dead short is still present, and I get a clicking sound from the instrument panel, which tells me something is back-feeding, probably, through the instrument cluster and stepping on the high beam circuit.

When I review the wiring diagram, and check the circuit, with the IGN switch on, I have power at terminal 56 at the dimmer, so that tells me the short is between the switch and the high beams lamps - or another device connected to the HL switch. BL-10/4 is a splice, and the 56a terminal feeds both the lamps and the high beam lamp in the cluster. If it's not backfeeding through the cluster, it's got to be backfeeding through the headlamp switch.

A review of the Exterior Lights diagram:

Instrument panel light OK.
Side markers, tail lamps, turn signals, lic plate lights, and stop lights function properly.
Low beams work properly.

High beams shorted. The low beam; side markers; and high beams share a common ground, and the low beams and side marker lamps are working properly. If the problem was on the ground side it should take down the side markers and low beams as well, but that's not case.

Terminal 30 of the dimmer switch is fed directly from the battery, which enables the running light and low beams. Terminal 3 of the headlight switch feeds terminal 56 of the dimmer switch, only when the IGN switch is turned on. Switching ON the high beams energizes terminal 56a from the dimmer.

Part of the problem is I can't see the schematic of the HL switch internals, but I do know terminals 1, 4, 2, 5, and 6 are hot with IGN switch OFF and when the IGN is ON. The only other variable, I haven't checked is terminal 1 which feeds overhead, door, glove box lights, and the clock. I plan on checking terminal 1 tomorrow, since none of these items are working. I may have a wire touching the body inducing the short, or the clock may be shorted.

Anybody out there had clock issues that impacted on other functions ?
 
Since the clicking sound I hear does sound like a clock cycling, I may check it first.

Thanks for the feedback guys and each post drives me a little deeper here.

S

[DogDiesel]

From the headlamp sockets, I'd inspect the wires for short, under the hood.
I'd take my 12v troubleshooting light, with aligator clip, and connect to voltage, and work my way back to the steering column.  Good news will be if I check the wire and light does not work.  For you, Murphy probably made the short in the steering column.

Pull the steering wheel, and lift out the dimmer.  check again.   
Short should be between steering column and lamp sockets.

Interested in what the results are.

Wayne

[Rabbit79]

According to what I see in the Bentley, that circuit Y's right after it leaves the dimmer switch with one leg going to the indicator lamp and the other to the headlights..... What I would do is dis-connect the indicator lamp leg at that Y..... If the problem persists, then your problem is on the head light side of  the circuit, if it goes away then it's on the indicator lamp side. That might help you narrow it down some.

[somolovitch3]

For grins, have you tried applying power to the high beam wiring AT the head lights? Go from the positive Batt terminal through a 10 amp fuse to the high beam terminal with the key switch OFF. If you get same result, Murfy luvs u.

[southernman]

Thanks guys for the reply, but I haven't had time to work on the truck for the past several days, but hope to get back on it next week. Plus, we're getting rain here in NC all week, so it might be a little while before I get back to it. It's not my main transportation, and I drive my Dodge 3500 dually 4x4 most of the time.

On the "y", it is shown downstream of the switch, but the two wires are connect "at" the switch, making it tough to disconnect. It's actually easier to remove the cluster, but I'm avoiding that for now, as I suspect it components on the 'other' side of the circuit that are shorting out.

Regarding hot wiring the high beams, yes they will light up if jumped out. Again, I'm pretty sure the shorts on the other side of the switch, so that's where I'm concentrating.

I've come to the conclusion that it's probably one of the circuits mentioned above in my previous post. I'll keep you guys posted with whatever I find. And you can rest assured, I will figure it out. I just need time to do so.

S

[CRSMP5]

this a 81+ caddy or westy bunny?

sounds like a ground back feed issue to me imo.. id look at them...

now westy have a bad thing... between the batt and inner fender is a crimped piece of steel over the red wires with tape.. in the main harness... that will turn green, and cause power back feeds thru the high beam switch...

how to explain this... ive seen it work 3 ways..

1.) turn on high beams makes car shut off... just like turning the key off..
2.) pulling high beams and holding allows car to run...
3.) pulling high beam switch makes gasser tach cut out, turns on other bat/oil lights.. diesel i do not know if it would stumbul, gas it kills spark pulse  (half way home from nc in a just purchased 84gti this popped up on me... was in caravan of vws just purchased and i was cruizin the gti)


seariously.. not joking.. not trying to be funny... some may thing with gm recal post that i am.. but really.. look at that connector..

[CRSMP5]

http://forums.vwvortex.com/showthread.php?6934235-Wiring-woes



saw that pop up on vortex a few day ago... thats the connector i speak of.. gas is 3 wires, diesel is 4.. diesels glow plug is added to that connector..

i get piece of copper tubing.. stuff every thing in then crimp it.. they do not sell a terminal big enough to do this..

[fatmobile]

Why do you think it's a dead short if no fuses are blowing?
 I forget what kind of car this is,.. MK1s have a couple 10 post plugs near the firewall,.. maybe one of those is corroded.

[CRSMP5]

because the high beam switch crackle/pops when the 3 examples above happen...