Cooling fan question

Dcalebaugh · 09-07-02, 07:03 PM

At what temp should the computer turn on the cooling fan on an unmodified 86?

Thank
Dave

vetteguy · 09-07-02, 08:53 PM

Should be 228- 230.

Top · 09-08-02, 01:10 AM

228 is correct. Buy a manual fan switch from Mid-America and you can turn it on at 190 when your stat opens. If you forget the 'puter will still turn it on at 228.

vigman · 09-08-02, 02:06 PM

228(+/- 5 deg)
Is the trip point for the MANUAL block sender.

The ECM will override @ 232 (+/- 5 degree) based on the sender on the FRONT of the mainfold.

The one Mid america sells will turn ON @ 200
and HOLD on till 180....

And the A/C request line
( which will trip the fan logic in the ECM) Goes LOW ( or open )@ 430psi
& will go HIGH ( or close ) @ 200psi

For the record.....

Vig!

Magnus · 09-08-02, 02:52 PM

Do any know when the other fan (the one in fron of the radiator) should turn on?

/Magnus

vigman · 09-08-02, 05:00 PM

So the the DUAL fan setup......

( 100%stock )

The ECM is the ONLY thing that controls the main fan!

The manual sender controls the AUX fan only!

Vig!

Magnus · 09-09-02, 01:24 PM

So far i know my car is 100% stock, Vigman what do you mean with manual sender? I haven´t seen the fan in the front rotating.

Best regards
Magnus

vigman · 09-09-02, 05:12 PM

On the ( drivers ) side of the head
Between Cyl 1&3
Is a bronze sender unit.. that has a Dark Green/White wire on it.

The sender had a ROUND pin...

Ground this wire... Did the relay CLICK? Is your fan spinning?

If not, the relay for the AUX fan is located on the fan shroud, above the main fan and a little twds drivers side.

The AUX fan is ONLY controlled by this sender/relay combo!

If you need relay pins/colors/ functions... post here I'll check tonight!

Vig!

vigman · 09-10-02, 10:16 AM

Pin D Dark Blue power feed from C FAN fuse
Pin F Dark Green/White GND from sender

These above 2 are the relay coil

Pin A Black/Red Power to AUX fan (N.O.)
Pin E Red Always HOT from Fusible link E
(Swinger)

So jump A to E.. does the fan spin?

If not Is pin E hot?

If yes( and no spin )

Is the fan plug pin B HOT?

If yes & no spin

Is the black wire going to pin A of the fan going to a good ground ( G117 )
( see my getting grounded post )

If yes & no spin

Fan motor toast!

******** now if the fan spins in the above steps**********

Ground Dr Green White

Does the fan spin?

If yes... bad sender.

If no.
( and you hear a click from the relay ).. Bad relay

Barrier · 09-10-02, 02:01 PM

The Aux goes on at 240 or so mine came on once when main fan relay went bad.
Vigman could you explain the AC pressure turn ons. I was not aware the fans were controlled by pressure. Would there be any problem with the inceased pressure when 134 freon is used?
Barrier

vigman · 09-11-02, 12:06 AM

http://corvetteactioncenter.com/foru...ighlight=A%2FC
This post describes my findings.

I think with 134 your fans would turn on a second sooner... that's all...no problem!

The HI side sender is the A/C fan request line for the ECM.

Vig!

Gixster · 09-11-02, 07:39 AM

OK dumb question time. My aux fan isn't coming on. I've swapped the relay with a known good relay, and it still isn't coming on. I've located the sender on the head with the green/white wire. Upon inspection though, I'm not sure how to remove the connector. I've tried pulling it, and pushing the sides in to compress it inside, but it's still not giving. I'd rather ask the dumb question then screw up the plug. Also, Vigman, is it safe to assume the color codes you mentioned earlier in the post for troubleshooting apply for an '89 as well ?

Thanks
Tracy

vigman · 09-11-02, 09:43 AM

It's a really safe bet ( but check it out anyway)

The connector latch ( for the temp sender) was a soft plastic...but over time & heat it hardens.. and get brittle.

Typically when you give it the CHARMIN SQUEEZE the shell flys apart... and you do have to squeeze it!

If you have a trouble light that's hooked to a good ground and poke thru the insulation that will be enough current draw to trip the relay.

Replacement shell covers are availiable at Pepboy's ( at least out here ).. and I had to replace mine.

REMEMBER 9-11-01

Vig!

FordNoMore! · 09-12-02, 08:15 PM

Well maybe the fan control system is different for the earlier C4's, but with my 92, I put in the manual fan switch, and I can operate the fans at any time,I can either operate one fan or both fans, but I do beleive the 88's only have 1 fan,I may be wrong though.anyway,If you install the fan switch You should be able to turn the fan on when power is passed to the switch, while engine running or not,unless 88's are very different setups then 92.

Magnus · 12-01-02, 12:33 PM

Thanks Vigman
When i grounded the Green/white cable the Aux fan turned on.
Do you think ecklers have the sender?

Thanks

Magnus