Frank_Blotto

As soon as I turn the key to ACC, the radiator fan goes on. This isn't normal, is it? Isn't it supposed to run only when the engine is getting hot? If it isn't supposed to be running, does anyone have any idea why it would be?

taman86

iTrader: (4)

When I bought my car, somebody had jimmy-rigged the wiring so that the fan was always on. This was in Arizona, so i assume it was done to help the engine cool faster. I've heard this referred to as hard-wiring the fan to the ignition key.

Does anybody know if there are any drawbacks to having the fan always on?

MdFormula350

fan life.


i would check to see if the relay is being grounded, seems like thats what is happening.

superv

yes there is, these factory motors were not intended or designed to be constantly on, they will internaly fail, seen this on customers cars

taman86

iTrader: (4)

I have driven my '86 TA like that for 110K miles. The fan comes on whenever I start the car. I have had the fan motor burn up, and also, I had to replace the wire connectors plugging into the fan motor.

My '89 GTA has dual fans, and they both come on, even when I just turn the key over, to listen to the radio. The car isn't even started yet, and they come on full power.

How should I start to address this issue?

superv

You could ask ten people, then youll have ten answers,
Get ahold of a good scematic, It's worth the trouble hunting down this info, I saved a few GM repair manuals from the dealer,
now Ive got every spec and scematic Ill ever need

Your ecm reads engine temp throgh the sender and then turns on fan relay throgh a ground wire, the ecm decides when the fan should come on not the ignition switch, that would bug me untell i fixed it

P.S. when your engine and feet are both cold in the morning
do you want your fan running ***** out?

taman86

iTrader: (4)

My heater broke 7 years ago, and I live in Las vegas, so it don't get to cold here.

I am wondering if my engine is running to cold though.
It runs at 130 degress going down the freeway, and 160 otherwise.

I keep getting trouble code 44 (lean exhaust), and I read somewhere that the computer adds more fuel when the engine is cold. I am wondering if running to cold is causing this code 44?

I can always unplug my fan at the fan motor, and run the engine
hard to heat it up, and see if it gets rid of code 44.

Also I may just wire a toggle switch, and jimmy-rig up a direct manually controlled fan switch. I'm thinking that will be the simpliest way to go.

87CamLT

My car used to overheat alot. I fixed all the problems, then my engine gave out from heat damage. My friend who put in the new engine set the fan to run all the time. I don't like it, but it keeps the temp down. After reading the negitive affects i think i am going to have it set back to its normal operation.

Lucky 13

I have a similar problem. I bought my 89 2 years ago, and the previouse owner did an ac delete , and wired the fan always on. i think i have finally found the relay, and the connector for the fan switch.
I had to go to a dealer and get the pigtail for the switch. There is an old broken switch currently in the block. I tried to get a socket on it today, but i just rounded off the corners.
I bought an Imperial Fan switch and instlled it twice and it no worky. I am at a lost at this time. I wil check the wiring from the relay though.
Does the wire going to the switch have a grey connector near the top of the engine? The wire comes out of the bundle and has a grey disconnect then it ran to a black disconnect. That is all i had until i bought the pigtail.
If i am going in the wrong direction let me know. thanks

like Taman86 i am lucky if i get mine up to 160. although with warm weather approaching i am sure that will change.

simpleman

Really it is a pretty simple circuit once you get into it. Most times it is the wire or connector going to the Coolant Fan Switch located between #6 & 8 spark plugs. They tend to get brittle & fall apart after sitting so close to the exhaust for so long. The Fan Relay is mounted on a bracket on the firewall, driverside corner along with another relay for the fuel pump next to your brake booster. When you lose that wire, commonly green w/white stripe, you lose the ground to complete the circuit when the temp reaches 190-200 on that fan switch (switch closes & makes ground). The hot to the relay comes from a Red heavy gauge wire/fusible link from your starter. Black & Red take that hot to the Cooling Fan Motor all the time. So when the Coolant Fan Switch reaches temp it makes the ground to complete the circuit & your fan comes on. Engine cools down & the Coolant Fan Switch opens breaking the ground - Cooling Fan Motor goes off - Simple huh?

Simplemania

simpleman

Here is a simple schematic I made for my son & his 89 RS to go along with the last post. I also made one showing one of the adjustable aftermarket switches tied in if you want to go that route. That way you can decide at what temp your fan comes on & goes off. Hayden makes one (Part No. 3647) for about $35.00 you can find at most parts stores. It is adjustable from 160-210 degrees (see next post).

Good Luck,
Simpleman

simpleman

Here is a simple schematic I made for my son & his 89 RS to go along with the last post. I also made one showing one of the adjustable aftermarket switches tied in if you want to go that route. That way you can decide at what temp your fan comes on & goes off. Hayden makes one (Part No. 3647) for about $35.00 you can find at most parts stores. It is adjustable from 160-210 degrees (see next post).

Good Luck,
Simpleman

simpleman

Last one I promise! By the way the fan should come on when you turn the AC on.

superv was correct in that "Your ecm reads engine temp through the sender and then turns on fan relay through a ground wire, the ecm decides when the fan should come on not the ignition switch"
Keeping that in mind if your fan is always running keeping the temp down the ECM still thinks the engine is in the warm up mode causing you to run rich all the time.

Got money & fuel to burn???
(not with the cost of gas these days!)

Good Luck,
Simpleman

Pro

The ECM went out on my car, and oddly enough, when it gave way, the fans would always come on. I switched out the computer, and the fans worked correctly.

Lucky 13

I bought a new pigtail for the connector and a new sensor, and it still no worky so ibought a hayden adjustable and no more problems.
I would still like to have the original system working though.

PyRo9862

I would think you could get vice grips on the rounded off fan switch?
Also the first thing as I think you know by reading your post that you should look for are the wires that the AC used to turn the fan on (when the AC turns on so does the fan). Some systems work when the wires are disconnected it turns on, others when the wires are crossed it turns on. Find the old wires and figure out how they should be. Then you can work on that switch being stuck.

Randy82WS7

on most or all engine the fan is supposed to come on when you unplug the correct and actual fan sensor switch

the one in the cylinder head is and always has been the dash temp guage sensor sending unit since 1968 when it was moved from the intake to the head on sbc engine, also 283 was last in 67, 307 replaced that engine for the 68 model year

simpleman

Go to Chiltons & check it out yourself the sensor for the gauge is still in the intake next to the thermostat housing/neck on the thirdgens. Or...trace the wire back from the relay & you will find that it leads to the fan switch in the head - believe me I have swapped a V6 out for 335, swapped the harness & ECM during that ordeal so it was wide open & right in front of me. Not only that but I have also added the manual switch & have the fan working by use of the green w/white stripped wire going to the sensor between #6 & 8 plug on my 89.

Not doubting you Fast68 but just telling you what I have found. Read Willie's Updated Total Fan Control at the top of this forum & see what he has to say. Just don't want to steer anyone in the wrong direction because we all need a little help every now & then(especially me) & thirdgen.org is the greatest place I have found spreading a wealth of info for all to read if you have the time to dig for it.

https://www.thirdgen.org/tech/cool8single.pdf
"The fan is controlled mechanically through an in-cylinder head thermal switch."

Later,
Simpleman

Benm109

Where do they sell those Hayden adjustable switches?

Lucky 13

I picked up my Hayden switch from Pep Boys 24.99

Pro

Just bought Flex-a-lite controller from summit - like 80 bucks.

Actually I bought it for my truck, which has the old non-vs controller, so im swapping those out. I might use the old controller in the camaro (if I can keep the radiator hose from leaking).

Dante93GTZ

iTrader: (5)

I plan on buying a Flex-A-Lite #212 dual setup for my IROC.

It replaces the stock fan(s) and according to FlexALite will outperform any stock fans.

Pro

Yes I was going to do that also.
But I still think the stock fans pull plenty of air. No need to use up amperage.

SinthetikIroc

iTrader: (1)

gauge is in the driver side head.

the temp sensor in the manifold is for the ecm and the fan switch is on the pass side head

elcamin0_77us

gauge is in the driver side head.
the temp sensor in the manifold is for the ecm and the fan switch is on the pass side head

Exactly, here is a link to a article showing the sensor on the front of the Intake. http://www.classictrucksweb.com/tech/0402cl_tpi/

There's a book out by John Baechtel intitled "Chevy TPI Fuel Injection Swapper's Guide." It's got alot of good info including a section on Troubleshooting using a factory style guide.

Here's a link to my reply on a previous post here in the cooling section. After reading it, you should be able to come up with the answer. https://www.thirdgen.org/techbb2/sho...hreadid=231136


Bill

Mike92RS

Your fan will also stay on when you have A/C or Defrost selected.

Lucky 13

well in my situation, i dont have a/c. it was deleted except the compressor. i am just going to stick with my hayden adjustable. it works just fine.
beside i cant find the wire that is suppposed to go to the fan switch.i think it was chopped in the process of ac delete