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Wed Jul 18, 2018 12:07 am

I recently inherited a 73 bay window bus and can’t figure out why the generator light won’t illuminate at all. I got it home realized it wasn’t charging and found the wire from the starter to alternator not hooked up. Hooked it up and still no charge. Have read the idiot light needs to work to charge... if someone could please point me in a direction that would be amazing I have checked the bulb also and all the other dash lights work thanks so much cheers

Wed Jul 18, 2018 1:21 am

Welcome to The Samba!

First things first, it might be worth posting a couple of pictures of your engine. You first mention generator light and then alternator. I assume you have an alternator by the year of your bus.

Other than that, at this point you might want to get familiar with the wiring diagrams before you start diagnosing. The alternator and voltage regulator are on current tracks 1, 2, 3, 4. The idiot light is on track 39.

All pictures from http://www.vintagebus.com/wiring

Wed Jul 18, 2018 3:45 am

Will get some pictures in the am the reason why I mentioned both was just referring to the light on the dash has a g around it. It has a plug in voltage regulator mounted to the back of the firewall if that helps thanks again

Wed Jul 18, 2018 5:16 am

This thread might help too:

https://www.thesamba.com/vw/forum/viewtopic.php?t=672761

Have you triple-checked your wiring? Is the alternator harness intact, not burnt in places and connected to where it's supposed to?

Wed Jul 18, 2018 7:24 am

Ok looked at it a little more closely this am and noticed the blue wire to the light is unhooked can anyone tell me where that hooks up under the dash thanks again for all the help

Wed Jul 18, 2018 7:34 am

Read over and over again the wiring diagram that Furgo shared, all that you need to validate is that the wiring is connected to the indicator light behind the cluster and connected to the alternator. Mind you that this wire is one of the smaller ones coming off the alternator, since it’s only sending the “idiot” functions.
Best of luck.
Study the wiring, it will eventually make more sense to you man.

Wed Jul 18, 2018 7:39 am

Thank you I’m just trying to make sense on where the little blue wire actually hooks up under the dash it’s on the bulb side just the push on terminal is not hooked up thanks again

Wed Jul 18, 2018 7:54 am

You'll have to be a bit more precise than "blue wire to the light", and trace the two blue wires that come out of your T6 connector. One should go to the alternator light and the other one to the brake warking light behind the dash.

If you look at the wiring diagrams from earlier, you can follow the blue wire from the voltage regulator in the engine compartment. It's routed to the front of the bus as follows:

• It first reaches connector T6 (wire connector, eight point, behind instrument panel. Actually, it's more like on the steering column support bracket)
• It then goes to T1d connector (single-way, on the cluster of the instrument panel) and finally to the alternator light bulb terminal.

Here's a T6 connector picture:
Credit: Samba user Frozenbutt

I don't have behind-the-dash pictures of the alternator light terminal, but perhaps someone else can chime in.

Why do you have vacuum hoses underneath your dash?

Wed Jul 18, 2018 8:10 am

Thanks after your pic I found what I was looking for but still no idiot light

Could it have fried the voltage regulator since the main power wire to the alternator wasn’t hooked up??

Wed Jul 18, 2018 8:16 am

theturtlebus wrote: Thanks after your pic I found what I was looking for but still no idiot light

What does that exactly mean? We can't look into a crystal ball :)

E.g.

- Did you connect the wire from T1d to the alternator light terminal behind the dash and it still wouldn't come on when you turn the ignition switch?
- Did you actually test if the light bulb works?
- What else did you test/do?

theturtlebus wrote:
Could it have fried the voltage regulator since the main power wire to the alternator wasn’t hooked up??

I don't know what you had connected or disconnected, but if I were to guess, it didn't fry by not having a wire connected.

furgo wrote: This thread might help too:

https://www.thesamba.com/vw/forum/viewtopic.php?t=672761

I'd recommend reading the thread I linked to earlier ^. It shows a procedure to test the voltage regulator if that's what you're suspecting is at fault.

Wed Jul 18, 2018 9:30 am

Sorry about being vague I hooked the wire that goes to the idiot light back up to the connector and the wire hooked up to the starter from the alternator and no charging. Could the fact they disconnected the wires I talked about make the regulator burn up.

Wed Jul 18, 2018 9:54 am

did you have the instrument cluster out?

Wed Jul 18, 2018 10:28 am

No got it home from grandparents house he’s had it on a battery maintainer and fixed the brakes and a few other things noticed the generator light wasn’t coming on stateted looking into it and found the shop who rebuilt the motor never hooked the wire from the starter to alternator back up. I hooked that wire back up and then noticed that they unplugged thie idiot light also so traced that and plugged that in also. Still no light on dash or charging.

Wed Jul 18, 2018 10:57 am

the VR should have a blue wire coming out of it. The blue wire from the firewall goes into a connector that ties those two blue together - just the two wires connecting together in the plastic connector. Is that what you found disconnected?

Wed Jul 18, 2018 11:06 am

I found the wire from the instrument cluster blue one disconnected that I thought goes back to the vr correct me if I’m wrong?

This single blue one was disconnected and that went to my light

Wed Jul 18, 2018 11:33 am

The blue wire from the side of the 8-way connector that you cannot see on your picture goes to the voltage regulator. Or to be more exact, to another one-way connector (T1a) in the engine compartment first.

The two blue wires coming out of the same slot of the side of the connector that you can see on the picture: one goes to the terminal on the housing of the generator light behind the instrument cluster, the other one goes to the brake warning light.

You can correlate that with the wiring diagrams sent earlier. At the bottom of the diagrams there is a yellow line with numbers. These designate the current tracks for reference purposes.

The current tracks you need to look at there to understand how the alternator light wire is routed are 4, 5 (engine compartment side) and 38, 49 (driver compartment).

From your picture, one can tell that one of the blue wires from the 8-way connector goes to the side of the 1-way connector with the VW logo. That's what I would expect

However, where the blue wire coming out of the 1-way connector side with the WEGO writing goes cannot be seen. I would expect it to go to your alternator light bulb behind the instrument panel.

Also, again, if you haven't done it yet, I'd suggest testing the light bulb. Other than the correct connections of the wiring, it's the easiest and most basic thing to test.

Wed Jul 18, 2018 11:47 am

in the engine bay there is a blue wire coming out of the VR. That goes into a plastic connector. The other side of that connector goes to the blue wire at the firewall. That blue wire then snakes under the car in the wiring loom, and arrives in the instrument area where it was disconnected and you reconnected it. Make sure the VR end is connected too.

Wed Jul 18, 2018 8:13 pm

Just want to say thank you to everyone who helped me in this learning process I finally was able to keep following the schematic and what I gathered was the shop didn’t hook a wire up so they proceeded to disconnect everything that had to do with the charging system. Got it all back together and now I can say I honestly understand that system and have a good charge rate with a light that works... thanks again

Wed Jul 18, 2018 10:04 pm

Awesomeness.
Glad you got it sorted out, learn from those who give advice through direction of hands-on learning, so you can share the same knowledge on whatever that topic may be in times to come for another, cool guy who knew that buses were where it’s at, happy driving.

Wed Jul 18, 2018 10:49 pm

Glad you got it worked out. For future searches.
T2 wiring diagrams
https://www.thesamba.com/vw/archives/info/wiringt2.php

key
https://www.thesamba.com/vw/archives/info/wiring/baybus_7374_key.jpg
1973-74 Alternator highlight