T&T sending switch

[jal]

The T&T sending switch on my 90 hp '98 Johnson is not working. While the motor will tilt and trim the signal will not be sent to the dash board. I removed the switch to test and there is no terminal that can be seen on this switch. The part # on it is 586039. This is a $93.00 assembly which I don't think I need. As I can't get a multimeter on it I am now some what lost. Any help out there.
Thanks,
John Larkin

 

[ccnstlr]

Re: T&T sending switch

The test for this switch is an ohm test. Forget the specs, but there is a range from up to down of course. There should be two leads and a ground strap or the sort leaving the sender. It may be that your leads are cut off.

 

[jal]

Re: T&T sending switch

There is a black and a white wire going into the trim switch, there is a green ground wire with a terminal attaching to one of bolts going into the bracket.
The black wire and the white wire go into a braided race and up into the motor, I can not find them up there. I feel that I may need a new switch as the arm of the switch catches on the top of the motor and might have broken.
Thanks for the reply.

 

[ccnstlr]

Re: T&T sending switch

You have to ohm across the black and white and move the switch up and down but again I'm not sure of the ohm reading spec, I'd have to look it up in my manual. You may be able to purchase just the arm if your switch is ok. Would be a lot cheaper. Try moving the switch by hand and see if your indicator is getting the signal.

 

[jal]

Re: T&T sending switch

I have moved the arm - nothing. I have found the switch in the wireing diagram but i can't find the plug end up in the motor to test it. Do you know of any site that would just carry the arm. I do not know why they would charge $93.00 for the switch, seems like a turn off.

 

[Molaker]

Re: T&T sending switch

Marine parts are like gasoline. They charge that much because "we" will pay for it.

As for the sender itself, it is a simple rheostat (variable resistor). The arm moves a wiper along the resistor. If I remember correctly, the max resistance on my '82 140hp was about 700-800 ohms. There is very little pressure normally applied to the arm when the motor trims up and down. If the arm is broken, you may be able to repair it with some JB Weld or something similar. But, make sure you measure the output right at the sender with an ohmmeter before you attempt any repair to the sender. It may be okay and the problem is really (more commonly) a broken wire between the sender and the gauge.

Edit: Looks like the arm is p/n BMC-0342386 and lists for about $4.

 

[rickdb1boat]

Re: T&T sending switch

Across the black and white wire should show 1 Ohm all the way up, 88 Ohms all the way down. If you don't get that or its erratic, then the sender is bad. To test the gauge, have only the ignition wire and the ground wire hooked to the gauge (remove send wire). The gauge should show full up. Then short the gauge sender terminal to ground. It should show full down. Make sure the key is in the ON position for these tests.. To find the wire connector in the engine compartment, just follow the wires up though the grommet until you come to the connector...

 

[jal]

Re: T&T sending switch

Gentlemen one and all,__ Thank you! I need to wait for my grandson as I cannot pull the boat out by my self. I will then be able to get behind it and trace the wires to the plug. Will look in manual to find correct gauge wires, which may be shorted after putting in a sonar and gps unit.
Thanks.

 

[jal]

Re: T&T sending switch

The resistance all the way up is1.6, all the way down is 99.?? Thank you! Now I need to find the correct wires on the gauge. Iwill let you know how I make out.
I now need to button up the motor. It appears that there is a yellow substance around the plug, to seal that connection. Will liquid tape do the same job.
Thanks again, you all give me great confidence.