1986 LG4 with single electric fan...stock engine w/ 5spd and non-working a/c.

So, my fan stopped working....since i've replaced the relay (correct one) the coolant switch in the engine block and the sensor by the thermostat or vice versa.

I even replaced the fan motor.

When i straight wire the fan to the battery, it works fine, but when everything is connected the fan doesn't spin...the engine will overheat if i let it idle long enough.

the a/c or heat doesn't work so i never turn them on. The fan worked fine until one day i started the car and it just never spun again..real strange since this car is rarely driven.

 

try jumping the A and B terminal under the dash, then turn key to on. does the fans work during that operation? theres three coolant sensors. all go into block. Passenger, Front, and driverside. which one dude.

 

not sure what you mean by jumping A and B terminals...

I'm no mechanic, just trying to do this myself.

I replaced the senor (or switch) in the block on the passenger side about midway. I replaced the other sensor at the top of the motor near the thermostat. There are two wires running to it.

 

Check the orange wire thats coming off of the alternator wire near the battery. Its a fusable link and may be fried in two. My was..replaced with an inline fuse. I had teh same issues. Look good as it may be wrapped in black tape

 

to jump the a and b terminal, use a paper clip or wire. the terminal is under dash by your knees drivers seat. hard to explain. but autozone gives a free code checker. it looks like a key. um the terminals are like a female plugin, its where you plug in the scanner.

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| 1 2 3 4 5 6 |
| 7 8 9 10 11 12 |
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jump 6 and 5 terminals. and turn key to on, not start. and also did you use teflon tape around the sensors thread?

 

The fan is not ECM controlled on an LG4, jumping A-B won't do anything but flash codes.

There is only one coolant sensor. It's the one on the thermostat housing (for LG4). Replacing it to fix a fan issue is useless, due the to reason above.


@tarheel, since you know where the fan switch is, turn the key on, unplug the switch and ground the wire.
If the fan runs when you ground the wire, you probably got a bad replacement part.

If it doesn't, you have a power or relay issue.

Keep in mind, the stock fan switch temperature is 238°F.

A Delco D1855B (or equivalent) fan switch, 215-ish°F on temp, is a cooler alternative to the stock fan switch.

p/n sw505 IIRC from AutoZone. Their search will show you a cross reference number if you plug in the Delco p/n.

 

what he said

the fan is controlled by the fan switch, its in the head, passenger side between he rear two cylinders. It has one wire going to it. If you pull the plug off and ground the pin inside the plug, the fan should turn on, with the key in "run" of course.

Most likely its a bad fan switch, but keep in mind, like deadbird said, the stock switch is set really high.

 

I had the same problems, bad switches - could never get one to work for more than a month - even tried expensive ones like Hypertech. I finally gave up, and installed a seperate aftermarket fan controller by Flexalite - it's been great for over 3 years now, totally adjustable, provisions for always on/off switch in cabin - I'll never go back!

 

thought this may be the reason the fan doesn't come on....well, i cranked the car and it again overheated so i pulled the fuse to find another one blown.

Where should i start to look for what's causing the blow fuses?

god i'm really tired of this car...i drive it maybe 10 times a year and everytime i want to just 'drive' the thing more problems arise....along with this problem, the 'choke' light is now on and the starter is making strange noises and the engine is difficult turn over.....sorry, just blowning steam.

 

you have a short somewhere. See if you can jump some wires from the fan to a 9v battery see if the fan runs. If it does, the wiring has a short somewhere. start tracing wires