Auxiliary Fan

[adfac]

86 L98. Can anyone tell me about the auxiliary fan (not the coolant fan) ... the fan that is in front of the radiator. I can't find anything about it in the FSM other than it gets its power from the same circuit as the coolant fan. The fan runs from the time you turn the key until the time you cut the engine. I don't think this is right. And on top of that, it's really noisy. There should be a place where it picks up a relay but I can't figure out where. Does anyone know how this fan should work? Anything would be greatly appreciated. Thanks. ;help

 

[vetteoz]

the auxiliary fan (not the coolant fan) ... I can't find anything about it in the FSM other than it gets its power from the same circuit as the coolant fan. The fan runs from the time you turn the key until the time you cut the engine. I don't think this is right. ;help

In stock setup aux fan is independently controlled by a mechanical switch (goes to ground at switch ) in the head (position varies with year model ) not by the ECM as the main fan is.
Possibly someone has rewired yours to run full time

 

[Hib Halverson]

Your aux fan has either been wired to be on whenever the key is on or the temperature switch has shorted.

 

[geekinavette]

Your aux fan has either been wired to be on whenever the key is on or the temperature switch has shorted.

Or the AC switch? (can't recall if that controls the aux fan on those models or not, but seem to recall those two are connected in parallel)

 

[ken mohr]

In stock setup aux fan is independently controlled by a mechanical switch (goes to ground at switch ) in the head (position varies with year model ) not by the ECM as the main fan is.
Possibly someone has rewired yours to run full time

I agree. There is a thermal switch on the 89 in the driver side between 1 and 2 cylinder. It is either bad and stuck in the closed position or the fan was wired to run when the key is turned on.

 

[JAKE]

I agree. There is a thermal switch on the 89 in the driver side between 1 and 2 cylinder. It is either bad and stuck in the closed position or the fan was wired to run when the key is turned on.

You mean between cylinders 1 and 3, right?

Jake

 

[ken mohr]

You mean between cylinders 1 and 3, right?

Jake

Yes 1 and 3.

 

[geekinavette]

Is that the fan switch or the temp gauge sender? On the '84 the one in the driver's side head is for the temp gauge, and there is another one in the passenger's side head between 5&7 that is the fan switch (and yet another one in the front of the intake for the ECM).

Are later L98 engines different?

 

[ken mohr]

On the 89 the one between 5 & 7 is the one that runs the puller fan. It works off the ecm. turns on aprox 228* The one between 1 & 3 is a temp switch that turns on the pusher fan turns on at aprox 238*. Both fans run from relays. If you see an extra or added wire at the relay that is probably a ground closing the relay. Pull the wire from temp switch between 1 & 2. If the fan turns off the switch is bad.

 

[geekinavette]

On the 89 the one between 5 & 7 is the one that runs the puller fan. It works off the ecm. turns on aprox 228* The one between 1 & 3 is a temp switch that turns on the pusher fan turns on at aprox 238*. Both fans run from relays. If you see an extra or added wire at the relay that is probably a ground closing the relay. Pull the wire from temp switch between 1 & 2. If the fan turns off the switch is bad.

Hmmm I don't believe that's correct. Anybody have a wiring diagram?

 

[ken mohr]

Not sure if it is the same on an 86. My 89 is exactly that. I changed the temp switch to a Camaro # FS4. Turns on Aprox 215* and back off 200*. Cleaned out in front of radiator a ton of debree. 190* thermostat and it runs at 189 most of the time. The pusher turned on aprox 15 times all summer and the puller maybe 4 times sitting in stalled traffic. The 86 may be different or reversed. the thermo switch tip looks like a mushroom. I'll follow up with a pic later.

Can't get picture uploaded. Go to auto zone or other and look at pic of parts. A thermal switch has a mushroom type tip and works mechacicaly to close or open. That should be the one running the pusher in front of the car. Not the one between the engine and radiator.

 

[mako41]

Not sure if it is the same on an 86. My 89 is exactly that. I changed the temp switch to a Camaro # FS4. Turns on Aprox 215* and back off 200*. Cleaned out in front of radiator a ton of debree. 190* thermostat and it runs at 189 most of the time. The pusher turned on aprox 15 times all summer and the puller maybe 4 times sitting in stalled traffic. The 86 may be different or reversed. the thermo switch tip looks like a mushroom. I'll follow up with a pic later.

Can't get picture uploaded. Go to auto zone or other and look at pic of parts. A thermal switch has a mushroom type tip and works mechacicaly to close or open. That should be the one running the pusher in front of the car. Not the one between the engine and radiator.

I also have an '89, do you have a GM part # for that Camaro thermal switch, or year, engine, and model it came with?? I would like my auxillary pusher fan to go on at a lower temp for increased cooling. How do you know the operating temps of the two thermal switchs. I thought I read somewhere (Possibly my FSM?) that the OEM switch for an '89 came on at ~ 228 degrees F.

Any additional info or input would be great. Thanks.

 

[ken mohr]

I also have an '89, do you have a GM part # for that Camaro thermal switch, or year, engine, and model it came with?? I would like my auxillary pusher fan to go on at a lower temp for increased cooling. How do you know the operating temps of the two thermal switchs. I thought I read somewhere (Possibly my FSM?) that the OEM switch for an '89 came on at ~ 228 degrees F.

Any additional info or input would be great. Thanks.

The puller is to turn onn at 228* and the pusher at, I believe 238*.

I got it at Advance Auto
sku 5970644
mfg # TFS4
I BELIEVE IT IS MADE BY STANDARD

 

[TedC]

Last time I checked into this, found three Wells fan swtiches with recessed mount and a thread size of 3/8 x 18 at Autozone. All under $10 each.
SW502 238 degrees F +/- 8 degrees (stock unit for 1989 L98)
SW505 221 degrees F +/- 8 degrees
SW500 230 degrees F +/- 8 degrees
This TFS4 swich looks like it closes at even a lower temp of ~ 215 degrees F.

 

[ken mohr]

Last time I checked into this, found three Wells fan swtiches with recessed mount and a thread size of 3/8 x 18 at Autozone. All under $10 each.
SW502 238 degrees F +/- 8 degrees (stock unit for 1989 L98)
SW505 221 degrees F +/- 8 degrees
SW500 230 degrees F +/- 8 degrees
This TFS4 swich looks like it closes at even a lower temp of ~ 215 degrees F.

TS85 is the gm # I was after Advance Auto cross refed to fs4 or tfs4.The box has both numbers on it. Closes at 211* Which starts the fan. Turns fan off at 200*. This aprox temps. I paid 14.95 I think. It did what I wanted so it was worth it. Make sure you put anti cease on it. There was a company merge at the time. Auto Zone didn't have it. Ordered one over the net but it didn't turn on until 228*. Get that tsf4 of fs4 you will be pleased.

 

[mako41]

Thanks for the info guys! But I don't have any Advance Auto stores near me and I would prefer to use better made, more durable OEM GM parts if available. Does anyone have the car make,model, engine, year?? That the lower temp thermal switch may have came on as an OEM part? Thanks.

Ken you referenced a "TS85" GM # that closes at 211 degrees where is this # from?? It is not as far as I can tell a valid GM part #.

Thanks again for any additional input.

 

[ken mohr]

A GM tech gave me that number. I know there has been some mergers. I think they are all made by the same company Standard I believe. The one I have works like a Swiss er American clock. I cleaned out from in front of the radiator and it very seldom turns on. Only at long redlights with high outside temps.

 

[TedC]

Ken, Can you confirm the fan switch part number? TS85 and TS4 are both coming up on the ACDelco web site with a description of fuel pump strainer. Standard does make a TS85 part number that is a fan switch for a Chevy 305 with VIN E. That cross refs to SW500.

 

[ken mohr]

Ken, Can you confirm the fan switch part number? TS85 and TS4 are both coming up on the ACDelco web site with a description of fuel pump strainer. Standard does make a TS85 part number that is a fan switch for a Chevy 305 with VIN E. That cross refs to SW500.

I see that. It is a BWD TFS4

It is for a 89 to 92 Camaro.

Here is the link to Standard BWD division

http://www.bwdbrand.com/web_app/catalog/bwd_bgBulk.aspx

 

[TedC]

Ken, Thanks. I'll pick one up and measure the closing temp before installing.