Thanks again to Vader. The "power balance" test showed a bad injector....replaced it.....runnin' fine again....EXCEPT FOR: The damned fans quit runnin'!! They were wired thru an aftermarket switch from who knows where. Last night I wired 'em direct from the ignition side of the fuse block, to the fan motor power wires. Worked for a while, then quit, and melted down the fuse for the guages! Now, there's no power to the motors, and every time I hook up a new wire from the fuse block to the motors, it blows the damned guage fuse! Have the motors shorted out?? What gives??

 

Sounds like the fans are pulling to much current for the fuse, wich makes perfect sense.


If You want them Wired On all the time, Learn to use relays!

Run 10 gauge wire to the fans, Directly from the battery, With a 30A inline fuse in each, and through a 30A relay ( 5$ from radioshack)

The use your ignition to actuate the relay.



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60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver 15.26 @ 87.0
Reader's ride -> My Ride

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype

 

Yeah ... you should never power the fans from the fuse box. Factory fan wiring uses a relay. The fans are one of the largest draws of current and the wiring can't handle it. You could burn your car down. The fan should be powered directly from the battery by the use of a relay. The relay acts kinda like a switch and controls when the fan is getting power to run. If you wanna control the fan by a toggle switch then you use the toggle between the fuse box and the relay. This trigger for the relay will draw very little current. Use a relay.

 

Just to give you an idea of how much current the fans use, on my '91 Z28, I measure the current draw. Each fan used ~48 amperes to start (or inrush current) and then <0.5 seconds later, used ~17 amperes continuously. Measurements were taken at 14.2 volts.

Multiply that by two (afterall, you used the plural) and the inrush current is ~100 amperes (!) and the run current is ~34 amperes (at 14.2 volts).

Like the other posts stated, a relay is is the solution. Just think, if the wire you connected was not protected by a fuse, you'd have had a very good chance of having a car fire instead of just a blown fuse.

If you switch them on/off with a relay, you'll probably use <200mA per relay, with is within the current range of just about any toggle switch on the market.

[This message has been edited by Stuart Moss (edited May 22, 2001).]