jcartman

ok please help i have tried sooooo many things to get this damn main fan to turn on and after paying $18 dollars and trying to have a (expert)...... joke if you ask me answer the question im ready to destroy this damn car lol..... jk i love the car just want it not to overheat i have replaced the thermostat and battery in this car i know the radiator isnt clogged and thermostat is working correctly the fan is not coming on though when the car reaches high tempratures if im driving like 40mph temps go down everything is fine but if i sit for like 10 15min fans dont come on and car begins to overheat please please please help trying to fix my grandfathers old corvette only 75,000 miles on it and im sooo close right now just need to figure this fan issue out and im good to start using my baby

jcartman

as an addition to my original thread i have grounded my green sensor wire and can get the aux fan to come on just not my main one!!!

rodj

So what tests have you done so far?

Checked fan fuse?
Hotwired the fan to the battery to confirm the fan motor actually works?
Checked for power at the main fan relay?
Checked relay / connector?
Grounded the relay control wire ( green / white at relay ) to see if fan operates ?
Disconnected A/c pressure switch to see if fan runs?

jcartman

these are the following steps i performed thanks to my expert ohhh and it is a 1989 chevrolet corvette im not sure if it is a c4 or what i just know it was my grandpas and i'd like to get it running.... back to the steps first expert tells me to ground wire on passenger side near block and see if fan runs did that no fans no nothing..... then he had me check ecm/eng fuse fuse test good then he had me take the relay apart at the radiator shroud and test for 12v i had voltage at red wire but not at pnk/blk wire he had me jump the connector when i did that aux fan came on.... he said to replace the relay and the other one would work.... payed him 18dollars replaced 10 dollar relay and still no main fan lol please help if ya can

jcartman

ok so i just disconnected ac pressure switch and no fans come on i'm going to run hotwire to main fan motor and see if it turns on thanks for the lil bits of help to get me somewhere greatly appreciated

rodj

Get new EXPERT

That is why you must always state year when seeking help.
On your year ,that sender is for the temp gauge; on 84 it is for fan

Wrong relay , as you found out that one is for aux fan.
Do the same test on the main fan relay mounted on firewall

Ask for money back

jcartman

So i have been trying to find a relay on the firewall that you talked about earlier and found one in front of the battery that has 4 wires and one next to the brake booster more towards the center with 5 wires.... can you tell me which one is the right one i replaced both the one in front on the radiator shroud and the one in front of the battery but still nothing and yea i agree ive tried getting my money back and they wont do anything he got a bad review from me but not much more thanks again for the help

Solderhead

Assuming your vehicle is completely stock and no one has had their hands in it doing mods or the like, your primary fan relay should have 4 wires coming off of it.

A black wire with a pink stripe
A Red wire
A Dark Blue wire
A Dark green wire with a white stripe.

Follow the black wire with pink stripe from the fan, it should go straight to that relay.

If you want to see if the relay powers the fan, connect a jumper wire to the dark green wire with a white stripe and ground it to the battery, or another good suitable ground. This will simulate the ECM Fan control driver and energize the relay.
At that point the fan should activate.
If it does not activate from this simple test, Check the FAN fuse in the fuse panel.

Make sure you have the correct relay before you do this.

rodj

First up, jumper the red wire to the pink/ black wire and see if the fan runs.That confirms if the fan actually works

So long as the key is on

kenmohr

What are you calling high temp. The main fan shouldn't turn on until the car gets to 228*. Also check for garbage between the condensor and radiator. Mone acted like that and I pulled a 5 gal bucket of leaves, gum wrapers, etc.

SunCr

There's no fan fuse on the '89 - it's powered by a Fusible Link behind the Battery.

Main Fan spec is 226 degrees or 230 psi on the a/c high line opens the reference signal and that should drive the Fan (you've allready tested that by disconnecting the switch). Fan should also run with the Diagnostic Terminal grounded.

Main Relay is on the Driver's side Fender Well in FRONT of the Battery. ECM pin C1 drives the Fan and should have 12 volts when the Fan is commanded - Green/white wire. Switch side of the Relay - Black - is from the ECM fuse (and you know that's good or the engine wouldn't run). Fusible link is Red and should have power at all times. Black/red runs to the Fan.

Solderhead

If it has the aux fan, doesn't that make it a B4P RPO code? The diagram for that RPO code shows a blue wire and not a black one going to both primary and aux fan relays.

Although the FSM is showing in one diagram an ignition switched FAN fuse, and in the other diagram it's showing the fuse as the ECM/ENG fuse.

AGENT 86

89 dual fan

jcartman

wow thanks guys for all the great help i will definetly give your ideas a try and let you know the results great responses thanks again