wiring harness

[sioux888]

Hi everybody.
So, I'm rewiring my 1974 bus and it's been a nightmare, I've been restoring every single piece of the bus myself but I was trying to stay away from the electrical system since it's something that never been tempting to me as a new skill to learn, well, after struggling to find an electrician that has the knowledge to work on old Volkswagen cars near my small town I will have to do it myself too. Now, the tricky part about my bus is that it was made in Mexico, just for starters, a 1974 bus has still an original 1600cc upright engine, while the American version obviously has a different type. I've been checking for options on wiring harnesses and it seems Wolfsburg west makes pretty decent ones but the thing that catch my eye is that it seems they come with very detailed and easy to understand instructions on how to install it. Would you guys think that I will have some trouble to install a harness just because the engine it's a different type taking in consideration that those electric looms are made for American type buses? I mean, both, American and Mexican buses share the same functional elements like headlights, turning lights, stop lights etc. One thing that I checked in particular was the similarities between the Mexican bus and the American bus on elements like turning lights switch and ignition switch and they are basically the same.

What are your thoughts about this? Looking forward to hear some words of wisdom...

Thanks

[Amskeptic]

[Wildthings]

I would agree that you should be okay using the US harness for your years, but do expect to make some changes. Can't say for sure without seeing how things end up laying out, but it might be helpful to add a junction block where the wires enter the engine compartment.

[sioux888]

Hey! Thanks for the help guys.
I just ordered the loom, let's see how it goes.

[sioux888]

Right! I finally wired the whole bus just as in the wiring diagram, now I turn the key and the engine turns and when I pull the light switch, the two front signal lights turn on, same with the left and right taillights. the bus was missing all the relays in the fuse box so I ordered them; I imagine I still don't have any power on the headlights since the relay is missing, am I wrong on that? of course, I don't see any intermittent action on the signal lights cause of the lack of the relay too. Now, I just received the relays but I am a bit confused; in the wiring diagram, I can see that the Turn/emergency relay has 4 prongs labelled as 56, 56a, 56b and S but the one I received has 5 prongs contacts with S, 56, 56a, 56b and 30, I am pretty sure I ordered the part for a 1974 bus, so why is that extra prong in there? my doubts don't end there, it turns out that the dimmer relay has 3 prongs in the wiring diagram labelled as 31, 49a and (+) but the ones in the relay are labelled as 49a, 31 and 30 instead of the (+) showing in the diagram. any ideas ?

[Tram]

[sioux888]

Hi Tram, thanks for the info, yes indeed, I typed on my last post the relays the other way around but I installed them correctly. At the moment I have lights working all around EXCEPT brake lights and it was when I checked the bulbs that I found something confusing, in the wiring diagram it seems the bus should have 2 brake switches, but I just have one. I've been looking around to see if someone else has the same but nothing so far.

[sjbartnik]

You only need one switch to make the brake lights work, the two switches were mainly for redundancy and to facilitate the operation of the brake warning light which your Bus probably doesn't have.

Your main problem would seem to be you don't have any wires hooked up to your brake light switch
_________________
1965 Volkswagen 1500 Variant S
2000 Kawasaki W650

[sioux888]

good point sbjarnik, I took the photo just after I removed the little rubber boot and I unplugged the wires, as you can see on the photo the switch looks pretty rusty so I decided to install a new one. Even now that everything is plugged back there's no brake lights but I assume it's because I need to bleed and refilled the brake system with fluid to increase pressure and make everything work again, I believe this type of switch works with pressure from the whole brake system, am I wrong?

[sjbartnik]

You are correct, if there is a lot of air in the system the hydraulic pressure may be insufficient to activate the switch.

If you get the system all bled and still no dice, you can test the switch to see if it's closing. The cheap versions of that switch are known to be pretty crappy. If you must replace it, get a quality version from Ate or FTE and not the cheap Chinese knockoffs.

The switch can be electrically tested by removing the wires and simply connecting an ohmmeter across the terminals. Have someone press the brake pedal and resistance should go from infinite to zero.

You can also test the wiring to the lights themselves by jumpering the two wires together in the boot once you pull it off the switch. That should make the brake lights light up. Not sure if the brake lights are hot all the time or only when key on in the Mexican model.
_________________
1965 Volkswagen 1500 Variant S
2000 Kawasaki W650

[sioux888]

Hey, thanks a lot man!

I'll follow your advice on testing the stock brake switch, I'll see other posts about them being pretty good quality.

I wanted to check the wiring and I'm scratching my head over it, it seems everything is wired correctly according to the diagram, my tailight frames are properly grounded and the bulbs are working but nothing happens when I jump those 2 wires that comes out from the rubber boot that covers the switch.

[sjbartnik]

[sjbartnik]

A follow up question, which taillight version does this Bus have? Is it the '72+ style with separate amber turn signal bulb or is it the '71 and earlier style where the turn signal and brake light are the same bulb? If the latter, that adds some complexity into the system as there's an interface with the turn signal switch. If the former, then proceed with testing as above.
_________________
1965 Volkswagen 1500 Variant S
2000 Kawasaki W650

[sioux888]

Dude! You saved my day brother, Thanks a lot. I managed to fix the problem and I have brake lights already
Answering your last question, the bus has the 72+ taillights .
Now the only thing missing in my electrical system is to wire the horn. More posts to read hahaha.

[Wildthings]

[sioux888]

Hey! Thanks for the tip wildthings, sorry for the stupid question bro but, how do you add that extra relay and what type of relay I should get?

[Wildthings]

[sjbartnik]

[sioux888]

The problem was a pretty silly mistake, it was entirely my bad, I had the brake wires and the taillight wires connected in the same pin on the taillight frame , it was just matter of connecting the terminals on the proper pins.

At the moment I'm dealing with the horn, after a little while I found that relay that wildthings recommended, I wired the whole thing like in the diagram he sent to me but the only way to make the horn works is by adding an extra ground wire from the bus body and touching the metal underneath the horn button, I wonder if the absence of that short plastic sleeve between the steering wheel shaft and the sleeve is the one to blame.

[Wildthings]

You should have a jumper wire that goes around the flex coupling in the shaft. I believe there may have been more than one way this was done over the years. You likely need to add a ground to the horn as well.