Hey MGVWfan...

ubercrap · Post by **ubercrap** » Sun Feb 06, 2005 9:29 pm

When you were helping Longbeach412 trying to diagnose the starting problems, you said you had a way to bypass the seatbelt interlock for '74's? None of my books cover '74, so clue me in on this? Which relay is it?

Thanks in advance.

MGVWfan · Post by **MGVWfan** » Tue Feb 08, 2005 5:27 pm

Just got back online, I wrestled the PC from the kids

Here's the deal. The seat belt interlock thingy intercepts the RED/BLK wire from the starter switch headed to the neutral safety switch on the shifter (automatic) or direct to the starter solenoid (manual). It uses inputs from the seatbelt buckle switches to tell whether to enable the path, allowing juice to flow to the starter solenoid when you turn the key to the "start" position.

You can defeat the interlock by disconnecting the connectors attached to the buckle switches beside both front seats (at least that's how it appears to work on my '73's seat belt light, disconnecting the wires to the seat belt buckle switches shuts the blasted hooter up), but then if the relay in the seat belt thingy craps on itself, you're still stuck with no juice

.

I say, bypass the whole wretched mess

. Here's how to do it.

Reference these two pages from the Vintagebus.com site...

http://vintagebus.com/wiring/Type_4_USA ... 1973-1.jpg

http://vintagebus.com/wiring/Type_4_USA ... 1973-2.jpg

This will help you to read the diagram...

http://vintagebus.com/wiring/help-73+.jpg

On Sheet 2, Zones 29-35, you'll see a rectangular box with a bunch of wires coming and going, Drawing # J34. That's the thingy. It's NOT the thing with the lamp that lights up when you don't fasten your seatbelts, that's K7 on Sheet 3. Since I don't have a '74 to verify the location, and the info I have doesn't give a location, I can't vector you in...but I'd look up under the dash or on the fuse/relay block for a big rectangular relay-looking thingy with 13 wires going to it, PARTICULARLY the RED/BLK (red with a black stripe) and WHT/RED (white with a red stripe) wires. It's the only device in the electrical system with those two color combinations hooked to it. If anyone's got a '74 and can post a picture of it, please do!

The two wires in question are the RED/BLK wire (4.0 square mm) going to terminal 50 on the seat belt thingy, and the WHT/RED wire (also 4.0 square mm) going to terminal "C". The RED/BLK wire goes to the neutral safety switch, terminal 50 (or straight to the starter, terminal 50), and the WHT/RED wire comes from the ignition switch, terminal 50. When identifying the RED/BLK wire, remember there's a second RED/BLK going to terminal "GB" on J34, but it's 0.5 square mm (lots smaller), so pick the big RED/BLK wire. Disconnect the battery negative lead (safety first), then cut those two wires at the relay. Strip and splice them, then solder them together (best to solder them and use heat shrink to insulate them, but a well-applied insulated butt crimp might work...remember, the starter solenoid draws around 20 Amps!). Reconnect the battery negative, then test it out.

While you're at it, you might want to install the "hard start", or "bypass" relay recommended by Bosch (and others). It powers the solenoid from a relay mounted at the starter, with the relay coil (around 1/4 Amp) being the only load on the starter switch and wiring. It boosts the voltage at the starter solenoid by a couple of volts under load with a typical (old and somewhat decrepid) starter switch. It'll also let you get away with using a crimp-type butt splice without guilt

. Here's a link to some info...

http://www.wolfsburgwest.com/wired/wire ... _03_01.htm

Any questions, ask! Good luck.

ubercrap · Post by **ubercrap** » Tue Feb 08, 2005 5:30 pm

Sweet dude

!!!!, disregard my other post...

D'oh, I realized my dad has my soldering gun...

ubercrap · Post by **ubercrap** » Tue Feb 08, 2005 5:53 pm

OK, cool, I located the wires, I'll let you guys know how it goes...

MGVWfan · Post by **MGVWfan** » Tue Feb 08, 2005 6:07 pm

Photos if you please Herr Krapf

!

MGVWfan · Post by **MGVWfan** » Tue Feb 08, 2005 6:15 pm

Oh, yeah, be careful with that small RED/BLK wire. If you should connect it up to the WHT/RED one by accident, and have the seatbelt switches on the passenger side closed, you'd get a short to ground when you turn the switch to Start, not good. It's the LARGE RED/BLK wire you want to connect to teh WHT/RED one, like I said in the previous post. I'd cut the small RED/BLK, too, and leave it disconnected, just to be safe and avoid confusion.

raygreenwood · Post by **raygreenwood** » Tue Feb 08, 2005 6:59 pm

Its easiest to just reach under the seat and pull the plug on each one from the socket bolted to the floor bulkhead. Ray

ubercrap · Post by **ubercrap** » Tue Feb 08, 2005 7:00 pm

It's actually pretty obvious which are the correct ones. I just went out and connected the aformentioned wires running to the relay, and voila, she cranks for just fine now! Ah, but she wouldn't run though. I went back and looked and there is gasoline leaking a little around at least 1 injector, so I've got to take care of that before I do anything else. At least I know I'm getting fuel back there... After I replace those injector seals, I'll test and see what kind of spark I'm getting...

Thanks guys, without this forum, I would be getting nowhere.

Arggh... I don't have a working camera, I'm going to buy a digital sometime here, maybe when I get paid on Thurs.?

MGVWfan · Post by **MGVWfan** » Tue Feb 08, 2005 7:16 pm

Glad it worked!

Yeah Ray, disconnecting the switches works, but doesn't bypass the crummy contacts in the seat belt interlock relay itself, often a cause of hard starting or no starting, and not just on VW's...lots of cars had that crummy interlock in the mid-70's, none survived very well that I know of.

raygreenwood · Post by **raygreenwood** » Thu Feb 10, 2005 8:18 pm

Those contacts will never be a source of hard starting. If they are bridged, the starter will not turn at all. Really, if you need to bridge them, its easier to do it at the neutral safety switch under the shifter bezel. Also...what IS a source of funky starting and is related to all of this...is the park position of the neutral safety switch itself. Even when everything is hooked up...if it does'nt want to crank...take the heal of your hand and push the shifter harder forward into park. If it starts, you either have dirty contacts in the neutral safety switch...or a poorly adjusted shifter cable or both.
Thats also what I have been getting at. If you pull the seat plugs out of their sockets, the car should start no problem...as it does not read anyone in the seat...so fastening the belt is no longer a pre-requisite for starter interlock. But...that will still leave the dash light on if memory serves...

. Ray

vwbill · Post by **vwbill** » Thu Feb 10, 2005 9:16 pm

Wow, that darm thing is still got you in a pickle!! Darn! I havent had to mess with any of that safety stuff much but remember it being a trouble sometime but I think most of the problem was that it just probably needs cleaning and inspection since think of the scary area that thing lives in!,lol!
If it wasnt the brake fluid getting around it or moisture issues..... Do you think it was more of a issue with the autos? bill
p.s. Hey sorry for this dumb one but what does it mean in the wiring when the stripe is white or black? Does that relate somehow to the current path??

ubercrap · Post by **ubercrap** » Fri Feb 11, 2005 11:21 am

No, I ended up bypassing just fine.