78 115 johnson tnt help

[townie]

I have a 1978 115hp Johnson that I replaced the trim switch in the throttle becuse the down botton quit. Checked the original with a ohm meter. Jumped the tnt motor plug , goes up and down fine, so thought it was just the switch. Replaced the switch and it cycled up and down for a few times , then quit. Checked the switch, fried ! Jumped the motor plug again still cycles up and down. What next? Thanks for any help.

 

[wavrider]

Re: 78 115 johnson tnt help

YOu have a relay box with that TNT, sounds like you may have something shorted in the relay's. Basically it is a solenoid.

Trace your wires down and you will find the relay box. Then you can ohm out the solenoids/relays se what is gone bad.

If you have a manual it should show the schematics.

 

[townie]

Re: 78 115 johnson tnt help

Yes ,remote solenoid in black box. All connections clean and tight. With battery connected there is 5 volts at the metal base but with the battery disconnected it shows no short to ground. Should the 5 volts be there? How else do you check the soleniod? Remember I can jump the switch pigtail and the tnt will cycle up and down. Thanks again.

 

[wavrider]

Re: 78 115 johnson tnt help

5 volts at the base.

I never seen this problem before, I would think thee should be only the 12v at the terminal and when switch is engaged then you should see voltage going to the motor through the solenoids.

It may not be a short it may be an over current problem burning the contacts in the switch.

Hopefully one of the exprts will reply to this post, many excellent members with years of experience on this subject. Sorry could not help you more.

 

[townie]

Re: 78 115 johnson tnt help

Thanks wavrider. Ill hang in there.