Hi everyone, i'm in need of guidance here, sorry if the question is so basic.
(1st things first, my car is a 87 305tpi iroc-z T5, dual electric fans)

My problem : the cooling fans don't turn, ever.

If i read the stickys correctly, these are the following reasons why the fans wouldn't start :
- Blown fuse (checked each one under the dash, all OK)
- Bad relay. I swapped the two cooling fan relays, no change.
- Bad fan switch, if i'm not mistaken, it's on the passenger side of the block, under the heads ? What can i do to test this one ?
- The fans could be dead.

Now here comes my real question, how can i fail-safe test the fans ?
I read in the other posts that i can ground the green-white wire and the fans should come on.

Should i just jump a wire from the green-white relay plug itself to the ground with an ordinary wire ? (is connecting to the battery negative the same ?)

Again i'm sorry if the questions are so "noob" but it's my first time and i don't want to blow any fuses and i want to know for sure if the fans CAN work, then the next step to check would be the fan switch is it ?

Another piece of info, i cannot manually start the fans with max a/c like in my 86, probably because the A/C was a little butchered from the engine bay.

Thanx in advance !

 

Check out my signature line. It's from a 1991 dual fan TPI. But yours should be about the same. The only differences would be that the 88+ cars turn on the passenger side fan by either
a) fan switch temp
b) A/C high pressure

Your 87 should turn the passenger side fan on by fan switch temp alone. Your driver side fan should turn on the with air conditioning regardless of pressure though.

 

Ok thanx, i'll find a test light and fused link for the tests.

 

Did the A-B ALDL test too, no fan spinning
Jumped green-White to ground, relay ticking but no fan spin.

 

I didn't go to the link in the second post, but I just had an issue with a bad fan switch,... The way I tested the fan was to lift the front left tire off of the ground,(easier to get to from below) unplug the fan switch wire,(between the rear spark plugs on the passenger side) stick a paper clip into connector, and ground the wire to the block. With the ignition in the on position this should spin the fan on the passenger side of the car. I recomend doing this when the car is cool because the heat sheild for the exhaust manifold if right next to the switch.

 

Don't forget -- 2 fan's, 2 relay's.

If a relay is "clicking", somethin wrong Lucy.

Check that the high current input connection to
the relay's does in fact have constant 12v.
These input circuits are tied together somewhere,
(if you really need to, I'll dig out my service manual
diagrams...), and connect directly to the battery.
Maybe corrosion, or fried fusible link.

Given that, I've wondered for some time, what the actual
current draw of these fans should be. I had one that functioned,
but kept burning relays, because it was drawing excessive
current. And then, how does one test DC current draw?
My journeyman electrician brother-in-law burst the bubble,
that the digital multimeters only test AC current, by measuring
the mag-field pulse -- which DC circuits don't do.

PS.
Just read the link. As usual, RF is spot on. His middle name
must be "Mr Miyagi", or "Certified GM Tech." If anyone can
help me on how to transfer the Service Manual pages, I'd
be happy to post whenever necessary. (If it means expensive
scanning-to-efile equip., you guys can contribute to Helms,
like I had to.)

 

Hi Travlr,

Many companies make DC Ampmeters for measuring DC Amperage. Fluke, Greenlee, and even Craftsman have them.