Where exactly are the locations of the fan switches in an 89 L98, and where is the best place on the net that i can get them from

 

You talking about the relays, or the aux fan switch. Relays are GM part # 14089936. One is located below the rad cap down a little bit from the top towards the engine, the aux relay is usually located above the battery mounted on the inner fender with a single screw. The aux fan switch which runs the aux fan when the temp exceeds 243 degrees is located on the pass side on the block near the knock sensor between cyls 6&8. Try www.gmpartsdirect.com for online GM stuff. NAPA has the relays under thier number AR-279.

 

yeah cause i turn on my a/c/ and the fan wont turn on, and my car goes hot! so now what i need to know if thunderracgin has good fan switches, or i should seek other products

 

If the fan won't run with the A/C, it's not the fan switch. Most likely you have a bad fan relay, loss of 12 volts to the fan or a bad fan motor. Locate the fan relay and unplug it. On the relay socket are 4 wires, two heavy guage and 2 lighter guage. The heavy wires carry the 12 volts to run the fan. Jump the 2 heavy wires with a paper clip or bent piece of wire and turn on the key, engine need not be running. The fan should come on. If it does the relay should be replaced. If you jump the wires and it does not come on either the fan motor went or the 12 fuse link that runs the fans is blown. If you are unsure of how to do this, you can substitute the heater blower motor relay for the test. They should be identical in appearance.

 

yeah i jumped them without turnin key and it did work, i think i need to replace the relay, thank u for the advice, u made a difference

 

My mistake about the key. The 12 volts to the contact side of the relay is ever present, the coil side is controlled by the ign key. Sometimes I type faster than I think. Glad to hear that you are making progress.

 

I have a similar question which I have posted in another area but thought I would doa repeat here.

My fan wont come on at all. I put power directly to it and it started to spin, which is a plus seeing I can rule the fan motor out. I took the relay to autozone for them to test for me sounded fine and I jumped the red and black/red wires in the relay connector and still nothing. With everythign connected, I unplugged the fan from the a/c hard line still no go. I also replaced the switch. The fuse under the dash is fine. The only question I have is apparently I have the fuse link to check over still, what am I actually looking for here? Is this the same thing as the junction block?

 

an added side not.

I am getting power on both the brn and red wires so I am wanting to say that the fuseable link is not an issue though.

I am a bit confused on this but does the fan switch connect to the ecm and then from there connect to the fan relay? or does the switch connect directly to the relay? If it goes through the ECM then it is very likely the ECM crapped out on me and that may be why I am also having starting woes too.

 

The fan relay has two heavy guage wires and two lighter ones. NEVER jump the lighter guage wires together. With the relay unplugged use a jumper wire and jump the two heavy ones. With the key off the fan should run. Most single fan cars do not use the ECM for fan operation they rely solely on the fan switch in the block. The fan switch when it gets to temp shorts internally to ground through it's threads and places a ground on one side of the fan relay coil energizing it and then the contacts in the relay handle the current for the fan. Don't mess with the relay, replace it. Get a GM or NAPA unit, they have been redesigned and are more reliable. If you use a jumper wire to test use on of the same guage as the heavy wires in the relay connector. Otherwise the wire will get hot and burn you. You can pull the wire from the fan switch in the block and with the key on simply ground it. The fan should then run if the relay is OK and also the 12 volts. Give me year and I'll check further.

 

Its a 91 RS 3.1L

This is where I am confused, all the diagrams show a wire going from both the coolant and hd coolant relay to the ecm.

Such as the coolant fan relay has a green dk/white that is shown going to the ecm pin e8. If they used the same wire to go t othe ecm and then on to the switch i can see this, otherwise the diagram is wrong.

The HD coolant I show a grey wire going to the ecm, pin d12? i believe.

I thought I had jumped the red and blk/red wires, which are the two largest before but I dont think I got anything. I will check again tonight. I didnt have time to do so last night due to classes. I know I have power coming from the red wire. So if I jump it and it doesnt work then either I have a problem with the fans ground, the fan hot wire or the a connector that has to do with one of those. possibly in the relay.

Also i am a bit confused with the coolant and hd coolant fans, do I have two fans and I dont even know it? I know i know, stupid question.

 

Okay, found the diagram. 3.1L uses the ECM only, no fan switch is incorporated. The ECM driver goes low at programmed fan turn on temp and energizes the relay coil. It is basically one half of the V-8 fan circuit. Red wire in socket should be ever present 12 volts, the blk/red wire is the other or fan side of the relay. They should both be larger guage wires than the coil control wires for the relay. Placing a suitable guage jumper across the red and blk/red should energize the fan. If it does not, either there is a wiring issue or the fan motor is bad. If it does run with a jumper replace the relay. Rarely does the ECM driver fail unless someone inadvertently places raw 12 volts to it. If you have A/C turning it on should also energize the fan relay and the fan.

 

There is a brown which is a smaller gauge and only has power when the car is on. The red is always hot, the green dk/wht goes to the switch and black/red goes to the fan. I know the fan works or at least it did at the beginning of this whole thing. I jumped with 14awg wire the red to the black/red and it sparked, which made me wonder, then i saw smoke come up from around the filter. I need to take a look at the wiring to see whats going on, my guess is either a grounding out or a bare wire.

 

Appreciate all the good suggestions, Danno! Both of my fans stopped working, so I did as you said and ran a jumper to each fan, both fans work. I went to NAPA and bought 2 new fan relays, part number was AR-226, made in China, and cost me 8.99 each. I swapped those in, and when I turn on the AC, neither fan comes on. But when temps got around 240, the passenger side fan kicked on. Does the sensor in the head control the passenger side fan, or the drivers side fan?

 

Ok, I think I've determined that the passenger side fan is the auxilliary fan, and the driver's side fan is the primary fan. So far, I have confirmed that the fans work, the fan relays are new, and the female connectors to the relays are working, as I can jump the 2 thick wires (in the fan relay sockets) and kick on each fan. The auxilliary fan is controlled by 2 things. (?) The temperature sensor in the head / block between the last 2 cylinders on the passenger side, and the air conditioning unit, somehow. I know that the block sensor is working, because when the temp hits 240+ the passenger side fan kicks on. However, when I turn on the AC (at any water temp), the fan does NOT kick on. And, with a working fan motor and a new relay and a good connector, the primary fan does not turn on at all. So, what should I check next? I have inspected all the fuses, and they are all good.

 

A fan request is sent to the ECM from the control head when A/C is switched on. Aux or pass side fan gets switched on and off by the temp sender in the block like you said and the pressure switch in the air cond system. Primary is driven by the fan relay which is switched on and off by the ECM. ECM looks at temp measured by the CTS on the front of the block, A/C request and whether or not the aux fan switch is low or high. You can diagnose 2 ways, either with the key "on" engine can be off, simple ground the aux fan switch wire. Both should run. If the primary does not
, measure the lighter guage or coil side of the primary with a voltmeter one of the 2 wires will have constant 12 volts with the key "on" and the other will have 12 volts until the ECM driver turns on. When it goes low the relay should click and the pri should run. Another way is to jump the ALDL connector and retrieve codes. During code retrieval the primary fan self tests and you can troubleshoot with a meter. It's rare, but perhaps the ECM driver was damaged. If by some chance the ECM has a problem you can get around that by switching both relay coils from the aux fan switch. The relay coils draw very low current and the fan sw is capable of running them both. Of course, a lower temp sw would be in order. PM me if you need help.