rear heated dash light perm on - 1302

[pgtips]

Hi,

I have a 1302 LS with heated rear screen. I recently had a nasty short out when one of my light switch wires came loose, it got snagged as the radio went into the dash, it was my live 30 and melted it. Luckily no fire, plenty of smoke. I rewired the cable to light switch which works as before so i think I was very lucky

What I may or may not have noticed before though is my heated rear light on the speedo cluster is on when ignition is on, remains dimmed in the off position and full on when switched on. I cannot start the car right now as it is still being built but it would start no problem.

I also do not have the rear screen installed at the moment so its an open circuit but I don't think this would stop the light coming on as there is a relay elsewhere per the wiring diagram although I am not sure where in the car it sits yet, so the switch trigger the relay main feed.

I traced the wiring diagram back and the heated screen sits on the same bar as lights on the fuse board.

In the heated screen there is also a relay and obviously the switch.
It also circuits via the regulator.

I'm not sure where to go with this, I do not expect the lamp to come on unless the switch is turned on so I must be getting feedback, and I wonder if melting the 30 to my light did more damage than i can see. It may have always been this way and I did not notice, the car has been off road for over a year being rebuilt. I've not actually had the pleasure of driving it properly yet.

Would it have made it to the relay, should I look at the switch again, any clues appreciated.

I can replace relay today, inexpensive and I have several.

Many thanks,
PG
_________________
1975 1.8l FI Auto Westy - Subaru converted
1971 356 kit 1600 TP - semi/stickshift
1971 1302 LS - semi/stickshift

Trim ring info here -> http://www.thesamba.com/vw/forum/viewtopic.php?t=559668
http://www.thesamba.com/vw/forum/viewtopic.php?t=451210
http://www.thesamba.com/vw/forum/viewtopic.php?t=479721

[sjbartnik]

I suppose it's possible that your short on the big red wire may have damaged the rear defogger relay (should be located under the rear seat).

The light in the speedo is powered by the switch on the dash. A wire is tied into the wire for the light which runs back to the relay to trigger the relay. The relay then puts 12v to the grid direct from the B+ terminal of the regulator since it's a high-current item.

There is supposed to be an inline fuse between the wire from the regulator and the relay.

You are right that the lamp should not turn on unless the switch is turned on; the switch is the only power source for the lamp. And it would appear that the lamp should be electrically isolated from the rest of the speedometer so the lamp glowing should not be a result of other lamps attempting to ground through that lamp's filament.

I guess the easiest thing to test would be to disconnect the black wire from relay terminal 86, make sure it can't touch ground anywhere, and turn the ignition on. Does the lamp still glow?
_________________
1965 Volkswagen 1500 Variant S
2000 Kawasaki W650

[pgtips]

Yes a very faint pulsing glow in one switch position, I assume the on position, else no glow.

Then on ignition full glow
_________________
1975 1.8l FI Auto Westy - Subaru converted
1971 356 kit 1600 TP - semi/stickshift
1971 1302 LS - semi/stickshift

Trim ring info here -> http://www.thesamba.com/vw/forum/viewtopic.php?t=559668
http://www.thesamba.com/vw/forum/viewtopic.php?t=451210
http://www.thesamba.com/vw/forum/viewtopic.php?t=479721

[sjbartnik]

[pgtips]

86 disconnected, faint pulse in one switch position, nothing on other.
Ign on, full green light in one position, glow on other.

The glow/faint pulse is constant ign on or off on the same switch position regardless ign on or off.

New relay fitted.

Hope that's clearer

Edit: reconnected 86. It seems as though the relay is lazy to switch over, like the current from the on off switch is delayed , but once it clicks off the light goes out when no ignition.
Same ign on, light pulses up to 4 times then I hear relay click and it's all off.
_________________
1975 1.8l FI Auto Westy - Subaru converted
1971 356 kit 1600 TP - semi/stickshift
1971 1302 LS - semi/stickshift

Trim ring info here -> http://www.thesamba.com/vw/forum/viewtopic.php?t=559668
http://www.thesamba.com/vw/forum/viewtopic.php?t=451210
http://www.thesamba.com/vw/forum/viewtopic.php?t=479721

[sjbartnik]

I suspect something is connected wrong at the fuse box, as the rear defogger should not be able to be switched on unless the ignition is turned on.

So with ignition off, you shouldn't get any light from the lamp regardless of switch position (and the relay should not activate when the switch is pulled).

With ignition on, the lamp should of course be off when the switch is off and should light when the switch is turned on.

The black wire that feeds the defogger switch should be connected to the same fuse as the black wire to the fresh air fan and the black/grey wire to the wiper motor. Make sure that it's not connected to a fuse that is hot all the time. It sounds like it may be.

But aside from that, you may have something funky going on in the switch itself. The next step would be to pull the blue/white wire off the switch and see if the light still glows dimly.
_________________
1965 Volkswagen 1500 Variant S
2000 Kawasaki W650

[pgtips]

I'm confusing myself with this. Your mentioning fuse box made me stop and rethink.

Initially i lost rear lights and assumed loose connection on the light switch. When i removed my stereo i found a loose red.

I attached this to 30 on my light switch (because wiring diagram shows red 30) and pushed radio back in, got a short out. Pulled radio to find terminal loose again and lots of smoke.
I replaced wire, reassembled and now have these issues.

So I've just disconnected the new red wire from fuse box - before doing so I turned on my hazard lights and got a short on fuse #7.
#7 is where the 30 from light switch would go according to super beetle light diagram schematics although I also read #9 on others.

Removed wire, Front lights still work, hazard OK, fan OK, rear heated OK, so I must have buggered up in trying to fix rear lights and it can't be #7 (they are all different believe it or not so next to try is #9.

I was convinced the loose terminal was the problem and when I attached 30 on light switch to fuse box I did get my rear lights back.

So I must have attached the burnt/replaced red to wrong fuse box terminal, it was #7 per pic below. Only other literature says #9. Can someone shed some light on this for me as #9 is taken.

I have 1 wire not connected at either end and no rear lights.

light switch, no 30 connection I assume = no rear lights.

_________________
1975 1.8l FI Auto Westy - Subaru converted
1971 356 kit 1600 TP - semi/stickshift
1971 1302 LS - semi/stickshift

Trim ring info here -> http://www.thesamba.com/vw/forum/viewtopic.php?t=559668
http://www.thesamba.com/vw/forum/viewtopic.php?t=451210
http://www.thesamba.com/vw/forum/viewtopic.php?t=479721