I have a 1990 1.6L turbo using MSPNP2, and I cant get the ECU to switch the fans on.
I've hooked up my fans to a relay in the engine bay, and I'm using the ground wire to connect the relay to the Megasquirt through the options plug. I have followed the instructions for proper setup and haven't left anything out to my knowledge. I put a jumper in the right location on the ECU, programmed the Megasquirt on my PC to turn the fans on at the set temperature through Output1, and still I have no luck with the ECU turning the fans on.
I have the relay set up properly and have tested the ground signal wire from the relay to ground and the fans turn on, but the ECU fails to automatically switch the ground through any of the outputs on the options plug. I tested continuity on the plug as well to test the pins and they all check out. I have thoroughly tested my setup and I've come to believe it may be a bad Megasquirt. If you know anywhere in my setup that could be wrong or have any advice with solving this issue, I would be so stoked. Thanks

 

I've ran in to this a few times recently. Not your exact issue, but someone saying: "I've tested everything and nothing is wrong, why isn't it working?"

Something is most likely wrong.

While I have experienced a few malfunctioning MS units, it's generally due to poor wiring. What generation MSpnp2 do you have, what pin do you have it pinned to, and what are your TS settings?

 

Can you tell us exactly how the relay is wired? What wire to what pin?

Is it something like
30 12v fused power
86 12v
85 signal from ecu (providing ground)
87 to fan

EDIT: I just read that you double checked the relay and grounding it manually does trigger the fan. ignore this.

 

I don't think its wiring related because the fans turn on if I ground the relay. I just need the Ecu to switch the ground through the options plug. I believe I have it programmed correctly in TS.
My TS settings are setup under programmable on/off outputs, with output1 enabled under the coolant output channel, when coolant > 188 threshold and 3 hysteresis. Power on value is off and active value is on. I've tested the Ecu to see if it would kick on the fans even at a lower temp around 110 degrees and still wont turn on.

 

What pin is the wire at?

 

The pin dedicated for output 1 relay control is number 24 in the manual, that’s the one I’m using.

 

Ok I found out what was the problem, the options plug harness wasn’t connecting its pins inside the ecu properly. I removed one of the wires from the harness and plugged it straight into the port I needed on the Ecu. Cooling fans get switched on now just as programmed. Just need the make sure it doesn’t get unplugged with some tape. Not the cleanest solution but it works.