parking light help!

[european_rocc]

I've been working on getting my car on the road and have found that i've got a lighting problem

When i first parked the car, it was because I thought the headlight switch had gone out.... again.

Well now i threw in a new headlight switch just to find out that no, that wasn't the problem... and the fuses are good


I've got the wiring diagrams right here (for an '85 scirocco not an '83) and it shows that the power from the battery goes through wire 58 at the headlight switch when the parking lights are toggled on (though for some reason 58R and 58L arent used, don't even have wires there ). With my meter i've verified that the grounds are good, and 12 volts goes where it ought to go when the switch is toggled. However, when i go to the tail light backing plate, the meter can't find power anywhere when the switch is toggled. I'm not sure what wires are supposed to get power when you want the parking lights on but no wire back there seems to get power, except for the brake lights and one of the tail lights. I've found continuity with ground on all the wires back there so i think that means that they are all grounded as well?

So anyway, do any of you guys have any ideas as to why i am not getting parking lights. The front parking lights dont work either, but i think the rear ones are more important at the moment lol.

(oh and for some reason my back right brake light gives power to the back right parking light and side marker every time i hit the brakes. So my back right brake light at the moment is three dimly glowing bulbs)

PIC!



my car is at the right, please help her get her tail lights back!

[european_rocc]

been doing some more investigating and started fiddling with the fuses.

Took out 7 and 8, and they are getting power... at first 12 volts but now it's more like 3. Probably user error.

Found out that when those fuses are taken out, the rear right brake light stops working altogether. What the heck did some of my wires weld themselves together?! That's starting to sound like more of a possibility. Maybe i should take out that fuse block

[cuppie]

First, I'll explain why the headlight switch is wired the way it is:
Across the pond, they have these things called "parking lamps." With the car OFF, turning the turn signal switch to 'left' or 'right' illuminates the side lights on that side of the car.
They're used to illuminate the 'road side' of the car, when parallel parked. Hence, "parking lamps."
Therefore, three outputs on the switch: 58 (license plate), 58L (left side lights), and 58R (right side lights.)
Since we don't have that here, VW simply used one output, and jumpered it at the fusebox to power the other two circuits.

Now, as to your problem:
frankly, what you're describing to me screams "crappy tail light grounds." Seriously.
Just because you measured continuity to ground when the lights are OFF, doesn't mean that the grounds are capable of supporting an actual load. Welcome to the concept of 'dynamic resistance.'
Always is better to do voltage-drop tests on the circuit. In this case, connect the meter to a light feed wire (let's start with the right brake light), and the circuit's own ground (the brown wire on that connector.)
Hit the brake. Note the voltage. If it sucks: move the meter's negative lead to a good ground point on the vehicle. Check again. Voltage now OK? Investigate the ground.

IIRC, the rear lights are grounded to a common point on the tail panel. Check it for corrosion.

[european_rocc]

Thanks for the tip! I'm going to try that. Though i am starting to think that the problem with my parking lights has to deal with something different because my front parking lights dont work either.

[european_rocc]

So the rear right brake light seems to get about 3 volts when grounded to the ground prong, as does the parking light prong when grounded to the ground prong. When i switch over to a good ground the volts remain the same. The same is observed with the other brake light: 10 or so volts but going only to the brake light prong.

Out of random i decided to arc some of the prongs together and with the brake lights toggled, my parking lights would turn on if i bridged the brake prong (powered) to the parking light prong, and by parking lights i mean ALL of them would work!

However on the back right backing plate, bridging the connections would pretty much turn off the back right brake light altogether and then light up all the parking lights but dimmer. After doing this my back rear brake light started working properly (without turning on the other two bulbs) but then i took off the rear ground and brushed/sanded and now i'm back to square one with that problem Almost want to rewire 58 entirely!

[cuppie]

Taking nothing apart (don't touch anything!!), I want you to do this:
Engine running (so we have stable voltage)... first, measure voltage at the battery (this is for reference.)
Next, take thy meter inside the car. Secure its negative lead to a known-good ground (like the ground tree.)
Turn the lights on. Measure the voltage at both S7 and S8, on both sides of each fuse. Note measurements as you go, and report back with results.

[european_rocc]

okay, with the engine running and the alternator charging i am at 13.35 volts at the battery.

With the switch installed and the backing plates plugged in (nothing taken apart) I get about 0.45 volts at both fuses. With the switch toggled on i am getting 6.80 volts at both fuses. I had to take the fuses out to test the voltages, if that makes a difference.

Let me know if there's another test i could perform that would help! I can also take pictures of anything if necessary.

FAKE EDIT: Let me point out that this problem occurred years ago while i was driving the car. Just one day while i was driving those lights went out. In fact because of that i turned onto a country road and plowed into a couple feet of water over the roadway (can't forget something like that! ) That's pretty much the reason why i suspected the switch itself not the ground

[cuppie]

0.45v at the fuse with the switch 'off' is fairly normal (you're measuring noise on the line.)
6.8v at the fuse socket, without even a load on it... that's bad.
(BTW: why did you need to take the fuses out to measure? There's a reason that there are exposed contacts on the top of an ATC fuse, you know... )

Given that you're only seeing 6.8v at an unloaded fuse holder, it's probably really craptastic if the fuse is installed (read: the lights are 'connected.')
And, this limits our area of focus to:
- switch
- switch connector
- dash harness
- fusebox

And, something I forgot to have you check:
for craps & grins, what's the voltage at S20 (license plate lamps)?

[european_rocc]

huh, i just couldn't find a way to get the probe in there with the fuse in! Thought i'd break something

Well i have a hunch its that fuse box. When i had the motor installed way back, the mechanic was like "oh hey your fuse box was all melted, but we figured it out" and i never really peaked behind it to see what he was talking about.

I believe we can cross out switch. I've got like 3 new switches now due to a mix-up and none of them make a difference when installed. And idk if it matters but i DID read 12 volts from the 58 wire on the connector (on the little brass part of wire 58 behind the connector) when i toggled the parking lights on, and as i understand it, that wire makes it to fuses 7 and 8? I base this on the fact that those fuses only get voltage when the parking lights are toggled on.

As for S20.... you are a bit ahead of me I havent even installed those lights yet! Oh, and i need to wire them up yet (i went a little snippy snippy when I took the hatch off for paint) For what its worth though those lights werent working either when i parked the car.


So IMO the main problem causer is in either the fuse box or in the harness under the dash. I guess I'll start with the fuse box and do some investigating, and maybe.... the dash. It has to be installed better anyway. Maybe i can get to that later this week when i got more time, until then more ideas are welcome!

This will be fun!

[cuppie]

Well, if you're measuring 12v at the wire (after it exits the switch), then you have both a good feed to the switch, and a good switch.
Therefore, problem lies with the wire from switch to fusebox, the connections at the fusebox (remember: that one wire is branched twice at the fusebox connectors, because it needs to feed three circuits in the box), or the fusebox itself.

Not terribly hard to pop the box out of its mounts, and measure voltages at the relevant connectors.
(the pins are listed in the Bentley diagram; better explanation of what's what can be found in the CE1 info at A2resource.com)

And... he mentions "melted fusebox - but, we "fixed" it.
I see a new fusebox in your future... The only "fix" for a corroded or melted box is a new one...

[european_rocc]

Yeah i remember it being completely shady. I mean the shop that i had put it together were pros, and they made my "no way in heck is going anywhere with anything working" car into "hey everything functions" car, but by the sounds of it that fuse box was pretty messed up and they had to do alot to it. Heh, i guess i was so excited about having that car running that i just forgot to check for myself, but now i remember how "bad" they said it was.

Now i can't WAIT to get a good look at that puppy!


aaaand yikes that's expensive! Looks like Meryl might be donating another part; seems like the '84 and '83 have the same fuse block.

[european_rocc]

alright dudes.... i don't mean to brag around but

I have uncovered the long lost art of Voodoo Magic!

I took that B plug right out of the back of the fuse box, plugged her right back in and BOOM i got parking lights!


But really, it looks like there was a little corrosion in there and i got pics!

B plug



where it connected to the fuse block



You can see it has some surface corrosion, but hey i'm just happy my parking lights work! Thanks again for the help!