Fan issue

[Ponymedic]

Completing my build and need help from y'all
Gocarted a couple of times and the coolant fan came on without issue. Tried to take a short run today and she overheated 100c+. Heres what I have done so far
Checked both sides of 30 amp fuse- good
Checked relay for contunity across 30-87 when I power 85-86-good
Grounded sender and checked connector at fan no 12v anywhere

Thoughts?
For the record I HATE electrical issues

[D Stand]

A few more details would help like where is your thermo switch? When you said you grounded the sender, did you ground the wire connected to the sender or the sender body?

[Ponymedic]

The sender is in the thermostat housing I pulled the wire and grounded to the engine block. I also used a test light to check for power on the green or blue leads at the fan

Thanks

[CraigS]

I think that either 85 or 86 has a problem. Convention uses one as + and the other as negative through the temp sender. I don't remember which is which but it will work either way. I see you powered the pair and the relay clicked so I suspect a wiring problem. I would first figure which is wired to the temp sender and then use a piece of wire to connect it directly to ground. Does relay click? Next is there power to the other one w/ key on? You checked for continuity at 30-87 when powering the other two but was there power at one or both when you checked. You obviously understand how the relay works so just need to check all 4 terminals and their wires one at a time.

[boat737]

Check to see if you have 12v coming into the relay at 30. Also check that 12v is at 87 with the relay active (and if you have it, there will be 12v at 87A when the relay is not active).

[Ponymedic]

Thanks guys good stuff. At the fan should I be lookin for 12v on dark blue when the key is on and 12v on both dark blue and dark green when the sender is grounded? Or does the dark green act as a ground?

[Ponymedic]

Problem solved had a 3 pin weatherpak connector at the fan somehow the pins got switched on the load side so I had one on the black ground and one on dark green thermostat ground none to power....oops

[GoDadGo]

Fantastic News!

[Ponymedic]

Yea back to basics. Best part is I walked thru it with my marine son who just got home dosent get better