Both of the electric cooling fans on my 89 Formula 350 are not running. I have gone through some diagnositics but am still at a loss...they do not run what so ever even with the A/C on. I checked the fan motor that is controlled by the ecm by directly connecting it to the battery...it turns on so the fan motor itself is ok. I replaced the switch that controls the secondary fan. Still not running. I did not check the fan motor for the secondary fan because I don't think that's the problem since both fans don't work at all. Anybody have any idea as to what could cause both fans to not run?

 

Have you checked to see if you're getting power to the fan relays.Could be something simple as a blown fuse(did some years use fusible links for the fans)or a broken wire or loose grounds.And if you do then do the relays energize which would complete the circuit to the fans.

 

The fuse in the fuse block is good. At the plug for the relay, I jumpered the red wire to the Blk/red wire...this according to the Haynes manual bypasses the relay and the fan(s) should have kicked in. Neither one turned on, so the relay supposively is not the problem. This is all according the diagnostics in the Haynes repair manual. The ecm controlled fan is grounded for sure though, I checked that.

What is really weird is that neither one works...I thought the two fans were totally different circuits. One controlled by a switch and the other by the ecm.
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I forgot to mention that the red wire going to the relay plug does have battery voltage as well. But that relay is for which fan...ecm controlled or switch controlled?

 

FWIW, I had the same issue with my 88 GTA. Chased that problem for weeks. Wound up being the fusible link right off the positive battery terminal.

Kevin

 

Hey gtaproject....I've been testing and checking wires and have come to the conclusion that the orange wire going to the relay does not have voltage...were exactly is this fusible link at... I really think that could really be it. Everything else is working.

 

The orange wires going to the two relays for both fans definetly does not have power. I can't find a fusible link off the positive battery terminal...what should I look for?

 

The mystery has been solved. I tried disconnecting the plug with the orange wires that goes to the fans next to the positive battery terminal because I was going to check the fusible link. Well, the plug looked ok on the outside but it was starting to melt inside and that was causing the problem. The plastic from the plug melting over the terminals caused the break in the circuit. The fusible link itself was ok.

 

Glad to hear it. Sorry I didn't reply sooner. Anyhow, I'm sure you saw the fusible link. I shot a pic of it before I saw you fixed yours. I'll post it for others that may consider the link a cause of their cooling woes.

You can't see the connection to the positive terminal, but from there the cable goes to a rubber grommet-like thing and then branches to a black wire and the red fusible link. You can see my new link connected to the old red link towards the left of the photo. Getting the fans to work, along with the fan switch from Mid-America (on 200 off 185) and a 160 thermo keeps me cool even in stop traffic.

Kevin