SX250TXRY OX66 Four wire trim motor..

[gunz@pc]

Hey everyone was wondering if someone could tell me what the "white" wire going to the PTT motor is for. It is connected to a double black wire female bullet connector. Thanks in advance for your replies.

R/
guns

[99yam40]

black is normally ground, so my guess would be ground or negative.

but looking in your service manual for wiring on T&T would be a good idea

[gunz@pc]

so out of the 4 wires coming out of that motor 2 are ground???? Crazy! So the pan switch doesn't work, the throttle control (dual or single) doesn't work with the white wire going to the double gnd but if I disconnect that wire and hook the double gnd to a good gnd everything works good as new. Gremlins!

[DennisG01]

On my engine that "white" wire you are referring to that is bulleted to twin, smaller gauge, black wires is not white. It is black (but not as big as the "real" ground, for lack of a better term). But if we call that the "4th" wire from the PTT motor, it IS connected to those twin black wires and everything works properly. As mentioned above, check the service manual wiring or physically trace those twin black wires and see where they go?

[gunz@pc]

Thanks for the info all I know for sure is there are four wire coming out of the trim motor: black, white, green and blue. The twin black wire have continuity to engine ground. Port engine has the same set up but that one works with all wire hooked up. Manual has nothing in diagram but it does show 2 grounds.

[DennisG01]

Do the twin wires on the port engine also have continuity to ground? If yes, then you know that that part of the circuit is OK. If no, follow the wires and find the short to ground.

There are tests that can be followed in the SM - try those?

Looking in my SM, there are indeed 4 wires shown leaving the PTT motor in the wiring diagram. Check again. I wonder if it has something to do with the thermo switch - possibly failed? I'm just guessing based on what I see in the SM, though. But check your manual again and look at the info on that switch and the test.

[99yam40]

Hopefully Bosco will post up a wiring diagram, I searched , but did not see one by googling .
did see a pic of a 4 wire T&T motor with a white wire with a bullet connector.
the other 3 wires had ring lugs on them

[DennisG01]

did see a pic of a 4 wire T&T motor with a white wire with a bullet connector.
the other 3 wires had ring lugs on them

That's exactly what I have, except for that white wire is black. That black wire is uncut - it goes completely inside the heavy vinyl/rubber protective sheath. It could just be that the wire color was changed from black to white or vice versa somewhere over the years. I "suspect" Gunz will say the same thing about the ring terminals?

Gunz, FYI, my PTT is currently on my workbench (rebuilding). But just for the fun of it, I Ohmed the two black wires (white and black for you) and got 800K. I was expecting either a lower number or infinity, but oh well. How does the resistance between your black and white compare to the other engine?

[gunz@pc]

Well thanks for all the help I must have been looking at another Service manual I had open but I did get to the right one and saw the "thermoswitch" Dennis was referring too. Thanks Dennis!! The readers digest version of this problem is if that white wire going into the double black and has high enough ohm reading you can change that relay all day and get the same result (2 other shops). if you ohm from the black wire (back probe) going into the triangle connector going into the t/t relay and eng and I got 1.3 M or aka a metric butt ton stopping the relay to function. But all is well except for not knowing what the function of the thermo switch is besides the thermo part. Thanks DennisG01 and 99Yam40 you kept me on track..

[DennisG01]

Don't thank me, yet... I could be way off base! I'm really just on the "fringe" of what I know about electrical diagnosis here. Others, I'm sure, can provide better answers - so take what I'm saying with a grain a salt... trust, but verify.

Here's what I'm thinking... According to the SM, the ThermoSwitch turns "on" and "off" (I assume this means "closes" and "opens") to connect that double black wire to ground. Assumably this is to protect the motor from overheating. If the switch has malfunctioned, it may be stuck in the "open" position. So by you connecting that double black directly to ground, you bypassed the switch which allowed the motor to work.

[99yam40]

I am fairly sure that even 2 wire T&T motors have switches that open up inside them when the motor gets too hot.

Boscoe needs to drop in and give some info on this white wire on 4 wire T&T motors

[gunz@pc]

I'm sure it has something to do with the safety of the motor and others may have it, that why when you bench test one using only the Sb and Lg wires she runs fine.

[boscoe99]

I am fairly sure that even 2 wire T&T motors have switches that open up inside them when the motor gets too hot.

Boscoe needs to drop in and give some info on this white wire on 4 wire T&T motors

Boscoe dropping in.

[99yam40]

Well looks like that is to a switch of some kind( probably thermal) that breaks the ground/negative on the T&T relay to drop it out.
I would guess it is auto resetting, and it is not resetting.

[DennisG01]

FYI, that matches exactly with my SM - thanks for posting that Boscoe - I'm sure it will help Gunz.

Yes, it's definitely referenced as a "Thermal Switch" according to the SM.