[timgixxer]

Just got my vette a couple of days ago and I've been sorting through the problems. The fan stays running fulltime while the ignition is on. I unplugged the fan switch at the head and they stay running. Could this be a bad ecm grounding the circuit to the relay? What else can I check? Thanks!!

 

[NICKO]

I would think that someone has bypassed the relay, and tied it in to the ignition. I had this on allmost every car Ive had :crazy:

 

[timgixxer]

Is there any reason to change it back or will everything work just fine with it running full time. Temperature stays between 195 and 205 always. Does the electric fan rob HP by working the alternator harder? Thanks.

 

[hoopty]

Most of us try to make the fans come on sooner than the factory 228 for the primary and 235 degrees for the secondary fan. I wired up a switch to turn my secondary fan on anytime I want and I have it turned on a lot and I have a hypertech chip that turns the primary fan on at 175 degrees and I have a 180 degree thermostat and my car will still hit 215 degrees in traffic. If I were you I would probably leave it alone. Your alternator won't work that much harder. I go to the strip almost every weekend and my fans are on all the time and it hasn't hurt my times at all.

 

[88TxVette]

:agree:

Leave it!
:agree:

I have a low temp switch that is 200 on/185 off as well as my ECM chip reprogrammed for the main fan to come on sooner also.

Cool is kool!

:thumbsup:

 

[blutoyz]

Is there any reason to change it back or will everything work just fine with it running full time. Temperature stays between 195 and 205 always. Does the electric fan rob HP by working the alternator harder? Thanks.

195-205?
I would say that falls into the "If it aint' broke don't fix it category":cheers:

 

[CentralCoaster]

I can guarantee you'll overheat when that fan motor burns up. I've seen this on two C4s which had fans running 100% of the time.

 

[Frank Blum]

I am going out on a limb here but I just have to believe the fan motors are 100% duty cycle. Later! Frank

 

[Vashner]

You need to find the bypass. Put a manual switch on it so you can turn it off above 35mph.

OR tear out the bypass and restore it to stock and work it the other way which is your sensors and thermostat etc.

 

[Hot Rod Roy]

Hoopty missed the point that you have an '84, which has a much simpler fan control circuit than his '88. You probably have a defective (stuck or shorted) relay. It's located on your left inner fender panel, below your master cylinder. The thermal control switch that controls the relay is on the right (passenger side) head, between cyl. 6 & 8. The ECM doesn't control the relay in an '84. The stock relay is marginal. I'd suggest replacing it with a 60 to 80 amp capacity relay. Having the fan operate only when required will lengthen the life of your fan. It's better to spend the money on a good relay than to spend it on an expensive fan motor! The fan will probably die at a most inopportune moment!
(P.S. I learned this the hard way.) :buhbye:

 

[wilber1191]

hot rod roy,

I have an 84. I replaced the relay last week because my fan that was running all the time, stopped running all together.

However when I replaced the relay. It went back to running all the time. I pulled the lead to the switch on the head. As I understand it, the fan should have stopped running if the switch was bad and in the closed position.

OR is the fan running at start up normal because I am parked and not traveling over 35.

 

[rayquayle]

Guys, don't forget the Fan Switch on the A/C Compressor. the '84 Fan Relay actually has two triggers. The Switch in the passenger head as described by Hot Rod Roy and the A/C Fan Switch on the A/C Compressor. If this switch is stuck closed, the fan will run whenever the ignition is on. As stated earlier, the ECM has no control over fan operation on the '84.

 

[wilber1191]

Thanks, I will pull that one next and see what happens. I thinck it is the one on the top of the compresor, two wire with a resistor in line, right ?

 

[wilber1191]

Sorry also, i have read posts with differant opions. Is it bad for the fan to run all the time. I live in central AZ it is hot as HELL here. Air into the rad is starting at about 200 degrees off the asphault at mid 12:00.

 

[wilber1191]

Vibration

I have a slight to moderate vibation that can be felt in the body of my ride at WOT about 2500rpm and up. It is during acceleration and when in park and netrual. This tells me it is not the trans or drive train or it would only happen in drive while moving. What should I check or look for?

 

[rayquayle]

Thanks, I will pull that one next and see what happens. I thinck it is the one on the top of the compresor, two wire with a resistor in line, right ?

No, should be a single tan wire, marked Engine Cooling Fan Switch in this drawing:

 

[Pila]

88 "Gremlins"

Re: Secondary fan
Gentlemen, you may be the end of a long nightmare! Just discovered that my secondary fan (green ground wire) which stayed on all the time, was evidently then connected to my KNOCK sensor?? (head mounted switch between forward two sparks plugs, driver's side)!!. There is also a relay on the inner fan shroud, is that the primary fan? Am I to understand that BOTH fans work off on the passenger side (head) sensor?

Is there a wire to go to the knock sensor?:smack

Thank you and Merry Christmas,

-Pila Chiles, retired
Hawaiii

 

[vetteoz]

Just discovered that my secondary fan (green ground wire) which stayed on all the time, was evidently then connected to my KNOCK sensor?? (head mounted switch between forward two sparks plugs, driver's side)!!. i

That is correct position.The drv side temp switch is the control for the 2nd fan only.
Suspect that switch is faulty ,does fan stop when you disconnect that wire?
Knock sensor is in block just above pan rail foward of the starter; pass side.

 

[Pila]

Secondary Fan L98

That is correct position.The drv side temp switch is the control for the 2nd fan only.
Suspect that switch is faulty ,does fan stop when you disconnect that wire?
Knock sensor is in block just above pan rail foward of the starter; pass side.

THANK YOU, Whew! Evidently it is okay, now that I know it's wired right and that (forward, port side) sensor is indeed for the fan and not a knock sensor. (Fan only comes on when I take that wire off and ground it, so it must be functioning okay).

Now if I can only solve the problem that has so far cost me $10 grand! Runs fine cold then develops a heavy loud drone "stutter" (definitely an electronic miss) when hot, loses power and mileage and runs like crap. Have replaced everything in the fuel system, new plugs, wires (didn't replace dist. module yet). Only code has been 32 so I just unplugged the EGR since I have headers and no smog pump. At least it doesn't code, but NO ONE has been able to figure out the problem. If you have any ideas I would really appreciate any input. Mahalo!:crazy: