83 Factory Cooling Fan running constantly with ignition on. Anyone had this issue?

[Waid302Mustang]

My 83 factory electric fan (V6) runs constantly with ignition on. It supposedly to come on either when coolant temp switch grounds the relay or AC is ON and AC pressure switch closes. The temp sensor is just a switch which closes when coolant reaches set temperature. The temp switch and the AC pressure switch are completely disconnected, and the fan is running with ignition on. I replaced the relay module and still problem.

If I disconnect Pin 6 which provide power to solid state fan control, the fan still run continuously. If I disconnect pin 4 (ground), then the fan works only when coolant temp switch is grounded but then fan will not work with AC. Pin 6 provide power to solid state fan control.

Once in a while my coolant temp would max out even though the engine was just warm and the oil pressure would read zero. I found an YouTube Video where the guy has later foxbody four cylinder and one of the ground was not connected and the fan would run all of the time and also the coolant temp would max out even though the engine was cold.

I am wondering if there is a bad groud somewhere.

Any idea ?

[KevinK]

I think you have the wrong relay controller. There's only 1 relay on that board. AC cars as in the SVO/Turbo 4, has 2 relays. The schematic you show has 2 relays as well. I think you have a non AC controller there.

[1984GTTurboVert]

His fan controller looks just like both of mine.
You checked everything but the temp switch.
Where is your temp switch located on that car?

[Waid302Mustang]

His fan controller looks just like both of mine.
You checked everything but the temp switch.
Where is your temp switch located on that car?

I did check the temp switch. All it does is grounds the relay sending power to the fan. I disconnected the switch and the fan still runs with ignition on. Before when everything was fine, I was able to manually make the fan come on by simply grounding the connector to the switch.

Thanks

[Chuck W]

Sounds like a bad controller. Either the solid state unit is toast, or that internal relay is pooched.

That little 2N2222(?) transistor(the little black thing to the right of the relay coil in your pic) could be bad. I've had those fail on the fan control circuit in my MegaSquirt install on the TBird.

[KevinK]

The 83 V6 fan controller is different from all the other cars and was only used in 83 with the V6/2.3 turbo and AC. I suggest you verify the part E2zb-8b658-b or E2bb-ab. I see a color code on some photos but I don't see any color call outs in the MPC. There is no indication in the parts book that these interchange with other models, engines or years.

I know Four Seasons did make a replacement fort the SVO with AC. The original SVO black box had TRW on in. Not sure about any others. The circuit board can easily side into the old or new box.

[Waid302Mustang]

Sounds like a bad controller. Either the solid state unit is toast, or that internal relay is pooched.

That little 2N2222(?) transistor(the little black thing to the right of the relay coil in your pic) could be bad. I've had those fail on the fan control circuit in my MegaSquirt install on the TBird.

I got a new controller and is doing same thing. I will get another one and try again.

Thanks

[Chuck W]

I missed the part about trying a 2nd controller.

It's also confusing that you said it still runs with the temp switch disconnected, but then you still can power the fan on by jumpering the connector?

Deciphering what you're saying that it's doing, it sounds like the relay coil on the Solid State (AC control) side is bad, or the relay trigger control from that side is stuck closed.

[Waid302Mustang]

I missed the part about trying a 2nd controller.

It's also confusing that you said it still runs with the temp switch disconnected, but then you still can power the fan on by jumpering the connector?

Deciphering what you're saying that it's doing, it sounds like the relay coil on the Solid State (AC control) side is bad, or the relay trigger control from that side is stuck closed.

Regardless if the temp switch is connected or not, the fan runs as soon as the ignition is turn on with AC in off position. This means the temp switch is not the problem. This started to happen few weeks ago. When everything was working fine, I was able to manually ground the temp switch connector to make the fan come on.

Thanke

[Chuck W]

So, it WAS working fine, then just started this key-on/fan-on thing.

Check your lead to the temp switch. Could have a short to ground in there. It looks like it runs through a connector or two to get to the switch. If it's not a bad controller, the fault lies in that wiring.

With the controller plug and temp switch connectors disconnected, check for continuity between Pin #1 on the controller and ground. Seeing as the switch grounds on the engine, if it's not connected you shouldn't be grounding that lead.

If it's not the wiring, it sounds like failed original controller and either a bad, or incorrect, replacement.

[Waid302Mustang]

So, it WAS working fine, then just started this key-on/fan-on thing.

Check your lead to the temp switch. Could have a short to ground in there. It looks like it runs through a connector or two to get to the switch. If it's not a bad controller, the fault lies in that wiring.

With the controller plug and temp switch connectors disconnected, check for continuity between Pin #1 on the controller and ground. Seeing as the switch grounds on the engine, if it's not connected you shouldn't be grounding that lead.

If it's not the wiring, it sounds like failed original controller and either a bad, or incorrect, replacement.

I am completely baffled by this one. I actually removed the wire completely from pin 1 to isolated it and fan still runs. This means something is going on with the AC circuit. Something causing pin 4 to ground tripping the fan relay. If I remove pin 4 which is ground, fan stops. If I remove pin 6 which powers the fan control, the fan still runs.

Thanks

[1984GTTurboVert]

Any update on this?
What happened to the pics in the original post, were they on Imgbb?

Here is some pics of the controller that came with my car.





The one i picked up to replace it is identical to it but with white lettering instead of yellow.
Based on the diagram that was up the smog pump has a line with the a/c that runs to the fan controller, could that be an issue?

[KevinK]

84 is a different controller.

[1984GTTurboVert]

84 is a different controller.

How so?
All the pics ive seen are basically the same.

[Waid302Mustang]

Any update on this?
What happened to the pics in the original post, were they on Imgbb?

Here is some pics of the controller that came with my car.





The one i picked up to replace it is identical to it but with white lettering instead of yellow.
Based on the diagram that was up the smog pump has a line with the a/c that runs to the fan controller, could that be an issue?

My relay looks just like that. I still have not solved the issue yet. I did order the factory manual and I hope it has some troubleshoot guide.



and I hope it provide .

Thanks

[KevinK]

It's a different part number. Not listed as interchangeable. Unless you have the actual engineering drawing, you are just guessing.

[1984GTTurboVert]

It's a different part number. Not listed as interchangeable. Unless you have the actual engineering drawing, you are just guessing.

Im not seeing or finding any actual reason why they arent.
The 8 pin controllers all basically use the same single terminal fan switch, with basically the same turn on temp and power the same fan motor.
I picked up some factory literature on the electro-drive fans and fan controllers and a few different year and model controllers to pick apart and look at so ill see what the reasons really are first hand, im tired of guessing.

[1984GTTurboVert]

My relay looks just like that. I still have not solved the issue yet. I did order the factory manual and I hope it has some troubleshoot guide.



and I hope it provide .

Thanks

Can you post a pic of where your fan switch is located and one of its connector?

[KevinK]

Did you put maximum load on it?

Head lights on high beam, ac blower on max, radiator fan on, ac compressor running, rear defrost on, wipers on.

I would not expect max output on the 1 G at 1800 rpm's. Try 3000 rpm's.

[1984GTTurboVert]

I think you have the wrong relay controller. There's only 1 relay on that board. AC cars as in the SVO/Turbo 4, has 2 relays. The schematic you show has 2 relays as well. I think you have a non AC controller there.

Here is a few pictures of a board with 2 relays like he is describing.







This one was for a 2.3l LTD II with A/C, i believe. Im still waiting for the "correct" part for my application.

[1984GTTurboVert]

I remembered i had the 83 book on cd and other than a few troubleshooting steps you basically already did not much there about it.
Here is the diagram in it for the 3.8 mustang/capri controller circut.




Unlike in the EVTM there is no indication of relays in the controller here.

[1984GTTurboVert]

Here is some literature on troubleshooting these fan controllers.
Hopefully they help someone searching for a solution to their problem since information is rather scattered on it.

[1984GTTurboVert]

Nothing i saw mention that the 8 pin fan controllers were inherently specific to their application in rear drive vehicles(you can see some diffetences in their diagrams), but it was specifically mentioned in the literature i have the 10 pin fan controllers for the front wheel drive ones were specific to their application and broke down some explaining some of the difference.