Ok working on an 86 that has the same fan problem as my sons 84 but I know that the 86 has a different wiring schematic. Anyone out there have the fan wiring schematic for an 86. Thanks for all the help

This isn't the wiring diagram, but still shows the circuits and diagnostic info for 1986.

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What Kevin posted is better than a wiring diagram. Let us know if you need any help!

Matthew

Thanks for the diagram. Someone had tried to fix this before by running a wire from the hot lead on the air compressor directly to the fan. I see that both inputs go through the ecm. Found that the a/c system needs charged, would this cause the ecm to not send a signal to turn on the fan? Replaced the fan relay and checked wiring on connectors but still not getting voltage to the fan. Will recharge the a/c system and see what happens. This seems to be a common problem on the c4 line, either runs all the time or not at all, will keep you posted as to what I find.

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Shouldn't. Looks like the signal to the ECM is either/or (either the a.c or the cooling switch).

Note on the chart that they say to disconnect the temp sender and that should "default" the ECM which should turn the fan on.

You can also use a jumper on the relay ground wire. Groulding that wire should turn on the fan and will tell you if the relay and wiring to the fan is correct.

Finally found that the fused link from the battery to the relay connector kept blowing when the fan comes on. It had a 15 amp fuse in it, replaced it with a 20 amp and it still blew. Anyone know what the correct amperage is? Put a piece of wire in to jumper and the system works as it should but should the fan draw that many amps?

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Schematic for early cars only shows the fusible link ( No rating given ) ;
On later cars ,Pri fan fuse is 30A

Thanks for the info, put a 30A fuse in and works as advertised. I'm suprised at the difference between the fusebox fan fuse (3A) and the fusible link

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3A is only the control circuit for relay ; not the power going through relay to fan



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