Thread: One big headache

I forgot to mention to also run continuity check on the shield. You should read continuity from the tm housing to one of the pins in the transducer connector. I don't know which pin, so check them one at a time till one reads. If no reading to one of the pins, you have a problem. Somebody gotta have ground.

The ground to head unit and ground to the tm battery is how the start battery and the tm batteries get tied together. Without this path, you get garbage because the signal has no reference point.

Originally Posted by Cane Pole

I forgot to mention to also run continuity check on the shield. You should read continuity from the tm housing to one of the pins in the transducer connector. I don't know which pin, so check them one at a time till one reads. If no reading to one of the pins, you have a problem. Somebody gotta have ground.

The ground to head unit and ground to the tm battery is how the start battery and the tm batteries get tied together. Without this path, you get garbage because the signal has no reference point.

I think I understand what your saying, but where would the transducer ground to the tm housing? Should the transducer not ground to the depth finders ground? And then that would run back to the starting battery? Not the tm since it has its own ground. Should they not be as separated as possible?

Sent from my SM-G900V using Crappie.com Fishing mobile app

the shield is tied to the tm housing internally. the trolling motor ground is tied to the tm housing internally thru a brown 18ga wire fused 3a to the tm ground wire inside the tm pwm control module. If the us2 is connected to the head unit, this ties the tm battery to the crank battery.

Some folks run an 18ga wire with a 3 amp fuse between the tm battery ground and the start battery ground. This wire accomplishes the same thing as the 3a fuse and wiring as I previously described in normal operation. This 3a in the tm housing has caused many headaches, especially tin boats.

when you operate the foot pedal power switch, a relay in the pwm module places power ( +12 or +24) on the positive brush and the pwm circuit pulses ground to the - brush. Brushes are isolated from the TM housing.

Did you check the fuse in the tm top head cover?

This is stuff to easy check. May not fix anything.

Bad connections could cause similar problems, so could a bad transducer. Too many to list as a possible cause.

I’m guessing you are using a tm version of transducer which is supposed to be more shielded.

my comments were concerning the built in sonar (US2).. Ignore me if this in not what you were talking about. I didnt see a transducer on ur tm picture, so I ASSumed.

Originally Posted by Cane Pole

my comments were concerning the built in sonar (US2).. Ignore me if this in not what you were talking about. I didnt see a transducer on ur tm picture, so I ASSumed.

I'm surprised you didn't notice the tm cane pole. This is blue ball old PD tm with a cane pole box located just under the shaft. No it doesn't have a built in transducer. And the wiring is a little out of the ordinary since it does have one of your little inventions. Lol

Sent from my SM-G900V using Crappie.com Fishing mobile app

Originally Posted by Pithon

I'm surprised you didn't notice the tm cane pole. This is blue ball old PD tm with a cane pole box located just under the shaft. No it doesn't have a built in transducer. And the wiring is a little out of the ordinary since it does have one of your little inventions. Lol

Sent from my SM-G900V using Crappie.com Fishing mobile app

I know this tm. Does the box still work? It has nothing to do with any sonar, only steering. No pwm involved either, just reversing polarity back and forth on the steering motor from the I pilot board or the foot pedal, whichever selected.

Again, I did not notice a transducer mounted on the housing, so I explained how the US2 is wired. Can’t remember crap anymore.



Sent from my iPhone using Crappie.com Fishing mobile app

Pithon, do you have a ohm meter? If you do try this, clean a spot on motor housing and pull head cover and remove fuse. Read for continuity from fuse lead going to motor and to motor housing to see if you got continuity. Sounds almost like that wire could be broken loose where it attaches to housing.