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Engine Specific Info and Questions => IDI Engine => Topic started by: 92EcoDiesel Jetta on March 10, 2014, 08:00:58 pm
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On my 92 Jetta, the cluster lighting always work when I turn them on, but would go black after about 15 to 20 minutes. Playing with the dimming rotary knob on the headlight switch does not help. It would always work again the next night, but only for 15 to 20 minutes. Turning it off and back on does not help. Does this sound like a flaky headlight switch? Anyone else with this problem before? I'll try to get a part number posted tomorrow.
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Sounds like the switch. Mine occasionally go dark and the dimmer is no help, but tapping or wiggling the switch sometimes brings them back. YMMV.
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Did you test power to the switch to make sure the supply circuit isn't cutting out? Could be a ignition switch concern, admittedly unlikely, but still rule it out.
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Did you test power to the switch to make sure the supply circuit isn't cutting out? Could be a ignition switch concern, admittedly unlikely, but still rule it out.
The headlights work fine when the cluster goes dark. Can it still be power to the switch?
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Per Bentley current flow diagrams, headlight is not fused. Fuse #3, which powers cluster light and license plate light is blown. New fuse #3 did not blow but still no power to cluster lights. Buzzed out fuse 3 output wire to headlight switch (gray wire) and it was open circuit. Applied power to the gray/blue wire to the cluster lights through an ammeter and it went over the 20 amp scale. There's a short somewhere in that circuit. I hate pulling the cluster on the Eco. I'll check the license plate light circuit for shorts first.
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When first switched on does the dimmer work correctly?
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When first switched on does the dimmer work correctly?
Dimmer always works when the cluster lights work. The first time I turn them on from a cold start (next night), it always works. After 15 20 minutes it would cut out and won't work again till the next night. Been doing this for 3 months, until a week ago when i replaced the headlight switch with another used one, after which I have not seen the cluster lights again and I find fuse #3 blown with the other problems reported above.
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Previous owner tired of blowing fuses put a self resetting circuit breaker inline?
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Sounds like more amperage on the circuit than the switches can withstand.
Similar problem with my headlamps, after I installed zenon headlamps in my Mk1 Caddy. Oh they were brighter, but my lights would go out after 10 minutes. Flipp them to high and same after a period.
Installed relays for headlamps and problem gone. There was nothing wrong with my switches.
Where could the extra amperage on the circuit come from? Center console wired in, radio loads, and even shorting wiring. On the flipside, nothing burns wiring or popps fuses worse than a bad ground.
I'd check loads and grounds.
Wayne
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Now that more info has been gathered, I am in agreement with Dog on this one. Chase those loads and grounds for all involved circuits on fuse 3, because something is wrong in there.
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Haven't done any trouble shooting other than at the headlight switch and the fuse panel. Waiting for it to get warmer before tearing into anything. Here are a few pics of the wiring diagram. Can anyone tell me how Fuse #3 is powered? It is hot with key on but I can't tell from the wiring diagrams how fuse #3 get it's power.
Following fuse #3 in the diagram, it goes to lower case "v" to another page to a relay socket #10 for a fog light. In my fuse relay panel, the fog relay socket is empty.
(http://i1183.photobucket.com/albums/x480/Ecodiesel92/20140317_172951_zpswusrqwoa.jpg) (http://s1183.photobucket.com/user/Ecodiesel92/media/20140317_172951_zpswusrqwoa.jpg.html)
(http://i1183.photobucket.com/albums/x480/Ecodiesel92/20140317_173035_zpsixet9pnx.jpg) (http://s1183.photobucket.com/user/Ecodiesel92/media/20140317_173035_zpsixet9pnx.jpg.html)
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It looks like it's powered through the headlight switch at first and second pull out position, which would make sense since that would act as a power for the supply side of the activator coil on the fog lamp relay, which looks like it's ground-side switched through the relay control circuit. I'd pull out S3 and check which side is getting power, and then see if the other side gets continuity to the grey wire at the light switch socket. If not, then check the grey wire with the green stripe. If it's as it says in the diagram with regards to circuit continuity and not grounding out on the body, check your switch from terminals 8/30 and 9/58 because if it's getting 15 power with the key on when it's off, you might have an internal headlamp switch fault.
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Did some more testing:
1. Gray wire on headlight switch terminal 58e is hot only with headlight switch plugged in and turned on.
2. No voltage on gray wire if fuse #3 is removed.
3. Fuse #3's top contact goes to 58e terminal of headlight switch (gray wire).
4. Fuse #3's bottom contact is hot only with headlight switch on.
My Bentley does not have a fuse only wiring diagram for my 92 Eco Jetta and I can't tell how fuse#3 is wired and powered.
About a month ago, I soldered a very light gauge wire to jumper the gray (58e) and gray/blue (58b) in an attempt to by pass the cluster light dimmer circuit of the switch. The cluster lights worked for a few seconds and the jumper wire burned up right in front of my eyes! Good I was looking at the burning wire while it happened and it didn't start a fire!
CrazyAndy, what do you make of all this? Do you think the switch powers fuse#3? I buzzed the switch out with an ohmeter, and there is no indication that it does. Maybe the dimmer circuit portion of the switch is defective as you say. There are 3 terminals to the dimmer: 58e, 58b and terminal 31 (which is ground).
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Weather getting warmer. :)
My headlight switch is about $40 to $50 for a new one. Since I hate replacing parts by trial and error, I am bench testing the headlight switch (mine is the type with electronic control , not the rheostat type) with 0.5 A load of incandescent bulbs (a little more than what my cluster lighting draws). The dimmer works fine so far. I am going to let it run on full brightness for a few hours and see if it cuts out on the bench. The switch is wrapped up with insulation to make it run as hot as possible. If it does not cut out, the headlight switch is not the problem.
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Headlight switch bench tested for 5 hours without issues. Next will be pulling cluster to check lighting circuit.
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I'm putting my money on the headlight switch, I know you just tested it out of the car, but maybe there are other factors inside the car like a misdirected deforester vent in the dash that's causing extra heat? After having the lights on for 15-20 minutes, things get hot on the sweeper (resistance), and the relitively low current draw of the dash lights can't make the gap and bam, lights out. That's my theory at least.
The switches come apart pretty easily, you could try cleaning/adjusting the sweeper.
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I'm putting my money on the headlight switch, I know you just tested it out of the car, but maybe there are other factors inside the car like a misdirected deforester vent in the dash that's causing extra heat? After having the lights on for 15-20 minutes, things get hot on the sweeper (resistance), and the relitively low current draw of the dash lights can't make the gap and bam, lights out. That's my theory at least.
The switches come apart pretty easily, you could try cleaning/adjusting the sweeper.
Yes, it can be a number of things, including the switch still, even though it tested fine on the bench. I put the switch back in the car and it worked about 5 minutes (dimmer had full control) and then died. I had a test light ready and the GY supply wire from fuse#3 was lit but the GY/BL wire (dimmer output to cluster) was dead. This could point to a bad switch or some high load dragging it down.
I pulled GY/BL wire out from the headlight switch connector and have it jumpered to the GY supply wire with an alligator clip (which basically bypasses the dimmer and make the cluster lights full brightness ( my normal setting). If this works, I am not doing anymore troubleshooting and will leave it as a permanent fix.
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Since pulling the GY/BL wire, bypassing the headlight switch, the cluster lights worked for a short while then went dead and fuse #3 blew. I checked the resistance of the GY/BL wire to ground and it fluctuated from 4 ohms (way too low) to 10 ohms (still too low). Another resistance measurement later it went back to normal (around 16 ohms).
I think the problem is in wiring from the GY/BL wire to the cluster or something in the cluster itself. The GY/BL wire also powers the defroster switch lighting so I will check that also.
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Got it fixed! I hope for good this time.
Pulled the cluster and found no shorts. Checked GY/BL wire resistance to ground with all loads disconnected and it was all over the place 4 ohms 8 ohms 12 ohms, even 1 ohm. Jumpering it to the GY wire would blow fuse #3 (more on that later). So I looked on other pages of the Bentley wiring diagram and noticed the GY/BL wire also powers the AC/heat control panel light, defrost switch light and cig. lighter light. These never worked before and I didn't know they were even lighted. Found a crimped GY/BL wire from the AC/heat panel light going to the cig lighter light. It had carbon on the insulation where the breach of the insulation was and likely where the intermittent partial short to ground was.
(http://i1183.photobucket.com/albums/x480/Ecodiesel92/20140409_145839_zpsh5aceask.jpg) (http://s1183.photobucket.com/user/Ecodiesel92/media/20140409_145839_zpsh5aceask.jpg.html)
Now all the lighting works including a well lit AC/heat panel which I hav is e never seen before.
The cluster lighting is much brighter than before so the partial short was pulling down the voltage.
I am not declaring total success till I run this for a few nights without blowing fuse#3, speaking of which I made this from a burned out fuse.
(http://i1183.photobucket.com/albums/x480/Ecodiesel92/20140409_165511_zps3hsdbzbl.jpg) (http://s1183.photobucket.com/user/Ecodiesel92/media/20140409_165511_zps3hsdbzbl.jpg.html)
Instead of keep blowing $$$ fuses while testing, I used alligator clips on a 2" long piece of solder as a fuse 1/4" apart. Everytime it blew, the 2" solder fuse is shorter by 1/4".
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Good to see you stuck with it till success.
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Good to see you stuck with it till success.
The cluster lights has been working fine since the repair with no cut outs so I am finally declaring success. It's been a head scratcher for a few months being an intermittent problem. I am glad I didn't buy another headlight switch or tear into the wiring bundles/ fuse box.
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This problem still bugs me in that the GY/BL wire output from headlight switch dimmer daisy chains to the cluster lights, then to the defrost switch light, then the AC/heat panel light, and finally to the cig lighter light (which was never connected because I found the wire was cut from the cig lighter and just hanging). The lighting for the AC/heat panel and defrost switch never worked in the 3 years that I've owned the car and the cluster light always worked with no fuse#3 blowing or intermittent cluster light opearation until a few months ago and it was all due to this partial short to ground of the GY/BL wire which got progressively worse. If it was pulling down the voltage on the AC/heat light, why did it not pull down the instrument cluster light voltage along with it?
The headlight switch that I have is the one with electronics dimmer and not the one with a rheostat. Maybe that has something do do with it?