Installing a GM 1 wire

DAUTRY3

MEMBER
1986 FORD F-150
5.8L
V8
2WD
AUTOMATIC
100,000 MILES

I took a 2G alternator off and installed a GM 1 wire, I am told the one wire is all I need to hook up. I did and I can't tell if the volt meter is working or not, there is no movement. Plus I installed dual electric fans with a new temperature sensor, it looked okay on the temperature gauge except it shows temperature way before it should have and when I throttled up the gauge pegged out on hot. Not sure the sensor might be defective or it got an overload of amps? Should there be another wire off the alternator to the voltmeter? There is a inline fuse between the alternator and battery, am I getting feed back from the one wire. 140amp alternator, 200amp fuse, installed on a 1986 F-150 with a 5.8L. There is a two prong plug with a rubber cap on it that the vendor said I didn't need to use.

3 Replies

STEVE W.

MECHANIC
12,963 POSTS

On the GM one wire units you only hook the single wire to a battery positive connection, either at the battery or the solenoid. That bypasses the dash ammeter and it will not work. There is no provision to connect an ammeter to these unless you use one of the heavy duty units, because of the current that the alternator can put out. Personally I don't like the one wire systems because most put out almost nothing at lower engine speeds.
As for the temperature sensor, it sounds like the one you installed doesn't work with a Fords gauges or it's defective. Is it a factory part or something that came with the fans?