Factory doesn't kick on until 238*f, is there any other models that come on a little earlier? Would prefer the fan to kick on around 190-205*. I need them to come on earlier.
Thanks,
Mike

 

I drive in parades and found by adding toggle switch to ground fan relay temp can be lowered on demand. But be aware this prevents optomal temp engine is designed to run in

 

I had thought about doing something like that, but I would rather it work on it's own. Not to sound like a smart butt (I do appreciate your response), but in my opinion that is waaaaaay to hot for an engine. I would bet they wanted to run the temp up that high to try and lower idleing (sp?) emissions, not for optimal engine performance or longevity. Imagine the oil temps and the unnecessary strain that puts on parts at that hot of cooling system.

 

Someone on this forum suggested Part# 609-106 from Mid America Motorworks www.madvet.com I bought this temp. switch last week, but I have not installed it yet. "Auto System Kicks Fan(s) On At 200 Degrees And Off At 185"

 

The stock fan switch for an 87 Buick Grand National is a 206 degree on temp. Sorry I dont remember the part number.

 

i think i found a switch by jet performance that turns on at 195 and off at 185. they say it's for dual fans. i'm waiting for an email from jet to see it it will work with the stock single fan. btw, i found the best price for the switch at froogle.com. i think it was $46 with shipping.

 

Those Jet fan switches are too expensive. I was going to get one at first but I looked around more and found cheaper ones.

Also, I think the same fan switch can be used whether the car has single or dual fans. In dual setups, one fan is controlled by the ECM, and the other by the switch, so there should be no difference.

 

I called NAPA cause my fan switch sensor went bad and they have the Buick Grand National one that turns on 220* and off at 200* (Close but a guess). IT costs $34.00. I ran a Standard brand and have to replace it every year,
The one from NAPA is an Ecklin(spelling) brand. I will try it and see how long it lasts. Hope this helps.

 

will the grand national switch fit with no mods? keep in mind that i would prefer to keep the single fan. adding a dual fan might mess up my worn out wiring. i guess 22 years baking at 238* has it's price.

 

I wouldnt have posted it if it wasnt a direct fit.

 

did you happen to get a part # for that "Ecklin" switch. i want to get one today! Thx!

 

Painless Wiring has one that comes on at 185*, turns off at 170*. it works good with the 160* thermostat. I had to splice some wire and connectors, though. it was pretty straightforward and simple.

 

The part number for the Ecklin is #FS113 and is at NAPA.

 

FYI: just talked to jet performance. their fan switch will not work with single fans. their switch only effects the aux. fan, not the primary cooling fan.

 

Thats odd. I don't see why it wouldn't work.

In a dual fan setup, the primary fan is controlled by the ECM, but the secondary fan is controlled by the fan switch. Thats why the fan switch cant control the primary fan.

In a single fan setup, the fan is only controlled by the fan switch.

 

Hypertech Cool Fan Switches
Fan Control, Thermostatic, 176 Degrees On/ 166 Degrees Off,
Kit ( HYP-4026 )

Sumitt Racing
$42.95

Ray

 

JET is full of crap, as usual. Jaimegmr is correct. On a single fan setup, the fan is controlled only by the fan switch in the cylinder head. It acts like the passenger side fan in a dual fan setup.

 

scuse my ignorance, but would the SW555 GN switch be for a standard late model Buick 3.8 or SC L67? Or just the turbo 3.8?

There are a hell of a lot of 3.8 and SC 3.8 parts here in Aus, probably not a GN on the continent though, so I'm hoping i'm in luck...

 

guys, i'm totally dumb. I need help finding the cooling fan switch. i have the F code engine (305 TPI) and the 1985 pontiac service manual shows a Fan Pressure Switch. is this the same as a cooling fan switch? it clearly shows the "cooling fan switch for the G code but not F code.

i putting a fan switch in from a grand national and i want to make sure i got the correct part. thanks!!!!!!!

 

The fan pressure switch is on the ac system, and turns on when the high side pressure exceeds a certain value..

 

dag, now i really don't know where the cooling fan switch is. HELP!!!

 

The switch for the radiator cooling fan is on the passenger cynlinder head.Between the last 2 exhaust ports.GM has a fan switch rated at 95c(180f) part# 3053190.After a while these things de-calibrate on start turning on later & later.Im using that switch listed & after 8 years it kicks in at around 200 deg,shuts off at around 185-180!

 

thanks!!! do you have any problems with smogging the car after you put the switch in?

 

Nope.No problems.Temp stays high enough for good combustion.However some fan switches dont let the engine run hot enough to burn the fuel completely.Making it harder to pass a smog test.180 is about as low as i would go.

 

No, thats not right. On a single fan setup its controlled by the ECM. There is no fan switch in the passenger head.

 

Then it seems like there are two different single fan setups.
My 1984 L69 305 Trans Am has a single fan controlled by the fan switch in the passenger side head.

Upon further research, I found that carb'd single-fan cars DO have a fan switch, while fuel injected single-fan cars DO NOT have a fan switch. The single fan in FI cars is controlled by the ECM and you would have to put in an aftermarket chip (or edit the one you have) to make the fan turn on at a lower temperature. I came to this conclusion by looking for the temperature fan switch part number for carb'd and FI Firebirds from different years at the ACDelco site. I was not able to find a fan switch for 1985 Vin F. Vin G and H do have a fan switch listed and they are both carb'd.

Sorry any confusion I may have caused.

 

to add to the possible temp switches available, @ www.rodneydickman.com. Go under engine tab and click on low temp radiator fan switch. (for some reason I can't get the direct link to load.) Most of his parts are for Fiero's but the temp switch is the same as the v8's. It's an Eclin switch on @ 195; off @ 185. $24 plus $3.50 s/h. Had no trouble with mine for last 2 years and best temps and price I could find.

 

so new question for everybody, where the heck to i get the ecm chip for the single fan fuel injection? btw, thanks to everybody helping me out. this site kick serious butt!

 

A quote found on thirdgen.org " Factory Coolant Fan Circuit Operation The fan is controlled mechanically through an in-cylinder head thermal switch and through the
mechanical A/C slider switch. The in-cylinder head thermal switch is designed to turn on the fan
when coolant temperatures reach 222°F (or higher) or when the A/C is turned on. There is no
ECM control for the fan on single fan applications." this was posted by willie. i have sent him an email ask for some clarification.
https://www.thirdgen.org/electric_co...pec_mod_single

 

I went to Autozone.com and looked at their wiring diagrams for 1986 & 1987 LB9 (they didnt have 1985 diagrams for TPI) and the diagrams only have one cooling fan controlled by the ECM. The only wiring diagram that shows dual fans for a TPI is starting in 1988. So maybe only 1988 and up TPI's got dual fans?

 

1985 TPI is identical to 1986 TPI, ECM controlled, no fan switch.

 

madmax is right

 

any suggestions for an ECM chip? i found a few from "hypertech." i'm trying not to go to crazy with it.

 

Why in the hell has Hypertech & Jet been selling lower rated fan switches for TPI engines then!!!Including vettes,I swear i saw this application in their catalogs/summit,etc many times!!!!Not that this affects me though,just wondering.

 

My primary fan (use to be single now dual) is controled by the switch in the inlet manifold, i thought the one in the head was a temp sensor for the guage in the cab?

 

Dont bother with a chip, besides the fact that Hypertech and Jet are garbage in a box. Get an aftermarket adjustable temp fan switch with a probe, the one that fits between the radiator fins works fine. Then you can adjust it to whatever you want whenever you want.

 

It must be an 85-86 thing then, because all TBI cars have a fan switch no cotntrolled by the ECM, and my dad's single fan 90 TA (before he converted it to duals) has a fan switch not controlled by the ECM.

Your absolute best bet is to convert your '85 system to an '86-'89 ECM system, or go for a '90-'92 ECM system. You can find the tech articles on this website by Mike Davis, or have my dad Dyno Don do it. '85 is the bastard year for TPI computers and nobody wants to touch it. Do no waste your money on a Hypertech or JET chip or one of those others like them. You can do the same thing as one of their chips by advancing your distributor 6 degrees and installing a lower temp fan switch for less than half the price of their chips.

Driver's side head between the #1 and #3 cylinders is the temp gauge for your dash. Passenger's side head between the #6 and #8 cylinders is the fan switch. Apparently its only on later year cars.

 

Ah cool, plus i have no ECM so there was no hope of that controlling when my fan comes on :P

 

the only problem with that is that i don't have a fan switch. its controlled by the ECM only. my only option to kick the fan on early would be a chip. i also fear doing any crazy wiring. damn this 85 TPI!

 

again, i agree with madmax. autozone has the aftermarket one for $20 that is adjustable to any temp you want. i would prefer the radiator fin probe, but they only had the probe in the actual water outlet when i was there. wrap it with the same white crap you use on pipes and it sealed better than the foam they give you.

 

so i've given up on doing this myself. i'm going to bring it to my shop and have them install a Hayden 3647 adjustable kit as recomended by willie:
https://www.thirdgen.org/electric_co...pec_mod_single
i'll let ya'll know if it works out! thanks for everybodys help!!!

 

my 89 RS has the coolant fan switch on the pass cylinder head. My RS has a single fan. I would like to convert to the dual fan system with the primary fan coming on via the coolant fan switch, and the secondary fan coming on via A/C operation. Does anybody have a schematic for that?

 

89 RS LO3 Single Fan, Had it rechiped but did not change the fan start temp...So what does do it on the 89 TBI...This post has confused me...I would like to have the fan come on sooner, as I have changed the thermostat...Runs cooler, but still would like the fan to come on sooner.

 

Mikey R, I have an '88 with the dual fans. I'm looking in my GM Service manual now and If I'm reading it right this is the story: The coolant fan switch which is located on the intake is set for around 230 degrees. This switch closes a low voltage impulse to the ecm which in turn energizes the primary coolant fan relay. Then there is the secondary coolant fan with it's switch located in the right side (passenger side) of the block above the starter. This is fused by itself directly from the fuse block to the secondary coolant fan relay. The switching portion of the relay travels through the switch in the block and ALSO the switch in the A/C compressor. The switch in the block is set to close at 243 degrees. The switch in the A/C compressor has a value in head pressure/lb.. So EITHER the block switch or the A/C head switch will turn on the secondary cooling fan. Putting the heater control **** in defrost also turns on the a/c and will activate the fan..even in the dead of winter! This is a design to protect the a/c condenser and compressor from excessive heat damage. I don't know if you have TPI or TBI, but I would think that if you're running a single fan in an a/c equipped car you already are wired the way I have described the secondary cooling fan circuit, and what you would be looking to do is add in a primary fan. Do you have provisions in your intake to add another coolant sw. to activate it? or perhaps you could wire a relay with a temperature switching probe in the radiator? The book I have here shows the diagrams for the "S" v6, "E" and "8" vin code motors. There might be more dwgs, I'd have to look. Hope this helps, Joe

 

hey if you got a 88 and later tbi its the fan switch in the passenger head that turns it on.my manaul says tpi is controled by the ecm.dont know but i have a 91 305 tbi and it has the switch.i just run a wire into the green/white wire at the fan relay on firewall on drivers side and run that wire to a switch then a ground so it is controled by the switch but if i get in town i can turn it on before it gets to hot for my tastes.really easy to do.and if you forget to turn it on the switch still works so you dont have to worry about forgetting it and messing something up.

 

yeah mines 88 TPI so I have both the intake primary and the block secondary switches. The dragonslayer sounds like he has a simple way of doing it

 

Don't Worry, Please delete this post.

 

yea my 89 is a TBI car, single fan. sensor on the pass cyl head. I just put the hypertech sensor in so when I get the car running we'll see if it comes on at 200F*, looks like Im gonna have to set up the dual fans myself. I'm thinking of using a separate relay and have it turn on the fan when I turn the A/C on. That seems to be the easiest.

 

i have an 89 tbi car and same with me switch in the head. does going to dual fans really help that much? I am putting in a howe radiator in about a week and it has a single fan. i just don't know if i should be running a dual setup.

 

I just found out that GM part number 3053190 is from a 86-87 Buick Turbo Regal (3.8L) or Grand National.
Advance Auto Parts (part number 35930) sells the switch for $6.96, but I had to order mine.