78 bus no blinkers, wipers or right brake light

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zabo
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78 bus no blinkers, wipers or right brake light

Post by zabo » Tue May 12, 2015 5:27 pm

Colin helped me get the bus running now i need to figure out some electrical stuff.
I'm terrible with electrical stuff, I cant visualize it, when i look at the wiring diagrams it I can't tell which way is which.

As of now headlights work, left brake light works, tail lights work.

Right brake light does not work, blinkers do not work ( the light on the dash lights a solid green but thats it) hazard switch does not work
Wipers do not work. Fuses appear good.

Where do I start with this?
Id like to figure out:
1. brake light
2. blinkers
3. wipers
60 beetle
78 bus

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sped372
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Re: 78 bus no blinkers, wipers or right brake light

Post by sped372 » Wed May 13, 2015 5:34 am

Stuff needs positive voltage on one side and a ground on the other to work. If it were me, I'd start with a simple voltage test at the item in question.

For the brake light:
If you're sure the bulb isn't burned out (swap to other side to check?), check for voltage at the light. Remove the bulb. Make sure one lead of your voltmeter is connected to a good ground, I'd use the ground strap right in the engine bay. Switch to a continuity check (ohms) and use the other meter lead to touch the area of the assembly that the bulb's socket sides would normally be touching. This area should be a ground and you should have very little resistance to the ground strap in the engine compartment. Otherwise your ground wire from the taillight assembly is corroded/broken or there is some corrosion in the bulb socket.

Switch your meter to voltage and then have a helper step on the brake. The little tab in the tailight assembly that touches the tip of the bulb base should give you a positive voltage reading (hopefully around 12!). I'm not familiar with the 72+ assemblies, but on other VW's I've occasionally found that tab to be somewhat corroded and/or not springy enough to maintain constant pressure on the bulb, even if it gives a positive voltage reading. You can try to bend it such that it has more firm contact with the bulb... don't do this with the system energized or you're likely to short something out. Make sure that tab can't touch the rest of the taillight housing, they need to be isolated from each other so all the current goes through the bulb.

If you have a good ground but no voltage, you have to start working back "upstream" towards the dashboard to find out where the voltage is getting 'held up' because something is either disconnected or broken. The same strategy applies to the other electrical items... start with the easy checks, making sure the item in question is actually getting electricity.
1971 Karmann Ghia - 1600 DP
1984 Westfalia - 1.9 WBX

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zabo
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Re: 78 bus no blinkers, wipers or right brake light

Post by zabo » Sun May 17, 2015 5:47 am

thanks for the great reply sped. i just picked up a voltmeter.

i have kids baseball game all day. hopefully ill have some time this evening to poke around
60 beetle
78 bus

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Amskeptic
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Re: 78 bus no blinkers, wipers or right brake light

Post by Amskeptic » Mon May 18, 2015 5:39 am

zabo wrote:thanks for the great reply sped. i just picked up a voltmeter.

i have kids baseball game all day. hopefully ill have some time this evening to poke around
If the emergency flasher and the turn indicators do not work, start by checking the flasher unit. It is the tall box hanging upside down closest to the drivers door on the fuse panel. It can get water damage in that location if the windshield happens to leak. If it is OK, the emergency flasher switch can be a bit of a pain if it is coming apart due to failure of the little tabs. Many of us have a computer harness size zip tie holding the switch together.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles

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zabo
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Re: 78 bus no blinkers, wipers or right brake light

Post by zabo » Mon Jun 01, 2015 6:35 pm

well I got the brake lights, turn signals and horn all working.
The horn ended up being both a broken wire connecting the two sides of the steering column and the metal strip not making contact with the steering wheel.

Wipers are still not working.

The 77-78 wiring diagram is really confusing to me. Why is there not a more visual version like the earlier busses!?
Can someone explain how to read them?

http://www.thesamba.com/vw/archives/inf ... _77-78.jpg
60 beetle
78 bus

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asiab3
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Re: 78 bus no blinkers, wipers or right brake light

Post by asiab3 » Mon Jun 01, 2015 9:40 pm

zabo wrote: The 77-78 wiring diagram is really confusing to me. Why is there not a more visual version like the earlier busses!?
Can someone explain how to read them?
I still can't read them efficiently, but from this post I have learned enough to use them when stranded:

viewtopic.php?f=48&t=232
1969 bus, "Buddy."
145k miles with me.
322k miles on Earth.

kreemoweet
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Re: 78 bus no blinkers, wipers or right brake light

Post by kreemoweet » Mon Jun 01, 2015 10:35 pm

The last paragraph in Amskeptic's post linked to by asiab3 is pretty much How to Use The VW Current-Track Diagrams in a nutshell. The later-style
diagrams are SO much easier to use to troubleshoot electrical problems in a logical and efficient manner. The earlier "visual" diagrams contain no information not
present it the later ones, except a very approximate indication of the physical location of major electrical devices, and that is information that is largely
irrelevant to the task at hand, and superfluous for any VW mechanic, or VW owner who is passably familiar with the innards of his/her bus. The later
diagrams are also superior in that they contain a great deal of info on the inner workings/connections of the various switches and devices, which is absent
from the "visual" diagrams.

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zabo
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Re: 78 bus no blinkers, wipers or right brake light

Post by zabo » Tue Jun 02, 2015 4:22 am

asiab3 wrote:
zabo wrote: The 77-78 wiring diagram is really confusing to me. Why is there not a more visual version like the earlier busses!?
Can someone explain how to read them?
ah i thought i temembered a post like this. thanks guys

I still can't read them efficiently, but from this post I have learned enough to use them when stranded:

viewtopic.php?f=48&t=232
60 beetle
78 bus

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