Dash lights - heat/fresh air lights

[Whaanga]

I’m working to diagnose why the lights that illuminate the heat and fresh air indicators in my bus dash are not working. They’re tied in to the lights that illuminate the speedometer and gas gage - which, are working fine. I exchanged the tiny bulbs from the instrument cluster and they work in the speedo/gas gauge but not in the heat/cool light mounts. I’ve cleaned the connections and made sure the ground tabs have contact with the metal mounting plates, etc., but no go.

The frustrating issue is these lights used to work.

What else can I check?

Thanks,
To
Jeff
_________________
Late 1973 Bay w/a transplanted 914 Engine

[telford dorr]

Measure both sides of the bulb with a voltmeter, relative to a good body ground. I suspect you'll find the same voltage on both terminals, indicating a faulty ground wire.
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST)

[Whaanga]

Thanks Telford dorr,

Please forgive my lack of electrical diagnostic experience but am I checking the bulbs or their mounting socket? And how does one evaluate the ground issue for these two non working light mounting g clips?

When it comes to this kind of work, I’m at an infant stage.

Thanks
_________________
Late 1973 Bay w/a transplanted 914 Engine

[telford dorr]

[Whaanga]

Thank you. This is helpful. The thing I still can’t get through my head is that the lights work for the speedo/gas gauge and are wired in series to the heat/fresh air sockets. I know the bulbs are working because I’ve swapped them in and out of each clip.

There is one wire that goes from the Non working sockets to the emergency flasher switch but it’s fully connected there.

I’ll work through this but I must admit, this sille little issue is kicking my butt.
_________________
Late 1973 Bay w/a transplanted 914 Engine

[telford dorr]

[Whaanga]

I'm still working to resolve the non-working heat/fresh air lights on the dash.

The photo below shows the back of the dash. I know the bulbs are good and I've followed the ground wires and they're connected to the proper spades. How does the grey wire with the red stripes shown in the photo get power? Is it transmitted through the metal plates? (remember I'm a novice when it comes to electricity.)

Thanks,

Jeff
_________________
Late 1973 Bay w/a transplanted 914 Engine

[ToolBox]

[busdaddy]

[Whaanga]

Thanks BusDaddy,

Yes, I've studied the schematic in the Bentley and am still trying to understand how to interpret the information.

For the grey/red wire in the photo, there is a ground wire that runs to the emergency flasher on-off control. And when the head lights are on, this control knob lights up.

For the other grey/red wire that goes to the other bulb (shown in my photo with electrical tape), the brown ground wire runs to the little brake warning light on the dash). And in my case, that brake warning light works properly.

I'm still not sure if I'm missing a ground wire or how else I can diagnose this (very small but slightly frustrating) issue.

Thank You
_________________
Late 1973 Bay w/a transplanted 914 Engine

[telford dorr]

Looking at the picture, have you considered that someone has swapped in 1976 a dash panel? That year shows the heater lamps wired in series (click schematic, expand, and see column 30):

That said, it should still work. Assuming the two bulbs are identical, using a voltmeter you should measure 12 volts at the feed wire, 6 volts at the jumper wire and the lower bulb plate, and zero on the brown wire and upper bulb plate (assuming dimmer rheostat set at max brightness, and measured to a good body ground).

_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST)

[Whaanga]

Thank You for your response telford dorr -

I'll follow your instructions and report back. The most frustrating thing is, these lights used to work. Not sure what happened from then until now.
_________________
Late 1973 Bay w/a transplanted 914 Engine

[telford dorr]

You will find something, one of the bulbs, bulb holders, or connections isn't making good contact.
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST)

[ivwshane]

Hold on! Are you guys saying the heater/fresh air diagrams are supposed to light up?! Is this year specific or is this also how it works on my 77?

Other than leds being used is this how that's supposed to look?

_________________
77 westy 2.0 FI
69 ghia coup 1600dp
70 single cab

[whip618]

these are the dash lights on my 74 after re-connecting the wiring and installing the bulb sockets.

phil
_________________
Life is simple....either you're qualified or you're not.
USSVI.......Pride Runs Deep
USSVI Life member and Holland Club member

Samba Member No. 3307

[tristessa]

Brown ground wire to both tabs, grey/red wire to both bulbs. Dims with the rheostat on the headlight switch just like the rest of the dashlights.

That's how they're wired on my '75 and it works perfectly.

[busdaddy]

[Whaanga]

Thanks All -

You can see my dash lights and climate control indicators with the non working lights.

I love the LED lights ivwshane, Where does one purchase these?

Also, this photo shows the emergency flasher control knob - it lights up when the headlight switch is on and has a ground wire that connects to the non-working climate control lights.

Being an electrical diagnosis dummy, how can this light work but the climate control lights not?
_________________
Late 1973 Bay w/a transplanted 914 Engine

[ivwshane]

That pic wasn’t mine but rather was pulled from the gallery. As for where you can get the leds, once you know the type of bulb it’s just a matter of finding the led equivalent (superbrightleds.com usually has a conversion chart).

When you find what bulb type it is post it here so I can get some too:p
_________________
77 westy 2.0 FI
69 ghia coup 1600dp
70 single cab

[busdaddy]