voltage regulator

ruddyboys · 02-11-2003, 06:20 AM

My 74 with a 70 1.7 had carbs installed from the PO. When he removed the FI it seems he removed the engine bay relay board and replaced it with a voltage regulator. I've traced my electrical problems (no horn, wipers, defroster blower and battery not charging) to this voltage regulator. Now the real problem, the car was not working when I bout it, alot of the wires were loose or broken. How do I know were the wires attach to the voltage reg? I know there are a lot of spade connectors not being used on the volt reg. Does any one this same setup or have pics and ideas? Im hoping to push the snow off this weekend and give it alook see.

Zeke · 02-11-2003, 06:49 AM

There are only 3 wires that connect to the VR via the plug in on the board. But all 3 come directly from the alt, IIRC. The relay board serves as a power distrbution center, a simple splice connector and as a relay board so high amp wires don't have to run all the way to the dash and back. It would take a genious to wire up a car w/o the realy board, IMHO.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Then I know several geniuses...

A lot easier to do on a race car, though, since most of the electrical systems in the car aren't needed. I sure wouldn't wanna do it for a street car!

There is one other cricitcal wire that gets connected to the voltage regulator--the blue wire to the alternator warning light. Without this light, the alternator will never charge. It gets tied into the D+ (red wire) circuit.

--DD

philinjax · 02-11-2003, 11:12 AM

DD,
The blue wire to the Gen (alt) charge indicator has no affect on the charging circuit, it simply indicates whether the battery is being charged.
Phil

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Are you certain of that? Jim Thorusen says otherwise...
http://www.pelicanparts.com/techarticles/914_alternator_troubleshoot/914_alternator_troubleshoot.htm

--DD

tryan · 02-11-2003, 01:23 PM

follow the diagram for the '73 and see how far you get.

my 74 has red (d+) brown ( d-) and green (field) .

i would get a board. much safer in the long run.

philinjax · 02-11-2003, 02:10 PM

DD,
I was wrong. After looking at the circuit, it occurred to me that the voltage regulator must have a reference voltage to determin whether to charge the battery or to back off. That reference voltage (and current) comes via the generator charge light. I stand corrected.
Phil

ruddyboys · 02-11-2003, 02:21 PM

Does all this mean that withouit the VR I can't get power to the horn, wipers ect? If so how do I go about replacing the relay board?

ejm914 · 02-11-2003, 03:52 PM

I think you have at least one problem not related to the relay board (or lack of one). The power for the horn and wipers comes from one of the red wires that attaches to the positive battery post, it does not pass through the relay board. With carbs, removal of the board is easier. The VR can easily be mounted elsewhere, the alternator harness that plugs into the board will plug directly into the VR, splice in the blue wire for the idiot light and your done. The heater (defroster?) fan will need a 4 wire relay mounted somewhere. Wires for things like the starter and backup lights get spliced together.

I removed the relay board in my '74. Mostly it is a junction box, wires go in one side and out the other. It provides an easy connection between wiring harnesses and mounting for a few components. It can also be the source of frustrating electrical gremlins because internals connections go bad. Good splicing and wiring will be more reliable than riveted brass strips embedded in tar for the past 30 years.