jms

iTrader: (1)

I may be new to most of the readers but have been watching from the sidelines for almost two years. Anyway, I just recently got my long term project '88 GTA 5.7 back on the road. The fans wouldn't kick on at the correct temp (according to the dash guage) so I wired a switch in the green/white wire on the driver side fan motor. At the same time I ran a wire to the temp switch above the starter and also to the same toggle switch inside the car and into a temporary location. Everthing worked fine-switched on and off like I wanted but I needed to mount the switch into a nicer place on the dash. I purchased a lighted rocker switch (with three posts on the back) and proceeded to connect it up. Then I couldn't get the light to turn on when I flipped the switch but the fans still worked. I got the bright idea that maybe I needed power to the light terminal so I ran a wire to the fuse box and proceeded to pop a fuse wherever I tried to connect to see if the light on the switch would work. So-I had another brilliant idea and hooked the battery charger (on 2 amp setting) to the terminal and POP... Now to the meat of the problem..the driver's side fan runs all the time I have the ignition switch on. Don't want that. Changed the fan relay(s) around, even put a new one on the driver's side fan wiring. No change. The passenger side fan still works through the switch as it should. I may have grounded the driver's side through some other place, but where? I even disconnected the driver's side fan wiring and hooked it to the passenger fan and it (the passenger fan)also ran when the ignition switch was on. What gives?

AZDave

As I remember, those lighted switches are meant to switch hot leads and light up as contact is made.
By supplying juice to the light post and turning the switch on, you effectively grounded the circuit, blowing the fuse.
You probably fused the switch internally and it now grounds the relay in either position.
Try disconnecting the switch and see if the fan still runs.

Stuart Moss

If the fan still runs (with the wire to the switch disconnected), then I'd guess the ECM is damaged because it is providing a continuous ground.

[This message has been edited by Stuart Moss (edited July 27, 2000).]

jms

iTrader: (1)

The fan still runs, with the switch completely disconnected if the ignition is on. It does not run if I take the relay apart.
I'm hoping the ecm isn't damaged. If so, would that affect any other functions beside the fan.
As for the fan, I believe I could wire a switch in the driver's side fan wiring and use it as the ground itself and leave the passenger side as it is. True? Thanks.

Stuart Moss

JMS,

With the switch disconnected, then (if I understand you correctly) the only thing connected to the left/drivers side fan relay coil negative wire (green/white) is the output of the ECM (which turns the relay/fan on/off). It appears that the ECM is putting out a continuous ground. I would suspect that this happened when you applied +12 VDC to the switch (which was connected to the ECM through the green/white wire). Worse yet, you applied unfiltered pulsed DC to the ECM when you hooked up the battery charger. See my post made 27 JUL at 0944 under LOW AMPERAGE WHILE DRIVING A SIGN OF A BAD BATTERY OR ALTERNATOR? W/IN

I would guess that nothing else was affected in the ECM other than the fan relay output.

You can check the ECM fan relay output to see if it's bad (putting out a continuous ground). On my 91 Camaro, the fan output of the ECM (dark green/white wire) is at the GE8 terminal, which is a green 32-pin connector. This pin should not be ground unless coolant temperature is high (or the AC in "on"). It should be "open". Ensure that your switch is not in the circuit when testing.

You can snip the wire going to the ECM after the switch, and then the switch should only switch this fan relay.

[This message has been edited by Stuart Moss (edited July 28, 2000).]

[This message has been edited by Stuart Moss (edited July 28, 2000).]