DF 150 Power Trim Blows Fuses

[Burrhead]

Two nights ago I was idling off the lake. While I was trimming the motor down and near the bottom of the trim range a 15 amp fuse near the battery on the white "control" wire from the motor blew. The engine immediately shut down and the trim switch on the throttle was disabled. As I was trimming the motor back up with the trim switch on the engine, a 10 amp fuse under the engine cover also blew disabling that trim switch also.

I have only been able to replicate this with the motor mounted trim switch. It will blow 10 and even 15 amp fuses every time I run the motor trim through the range from up to down, most of the time near the down limit.

Has anyone run into this before?

[Harper]

Never heard of that problem. Does it blow the fuse immediately upon operating the switch, or after the trim motor runs a few seconds?

[Burrhead]

Usually after it runs a few seconds - usually but not always at the bottom of the trim range.

[redlowrey]

Usually after it runs a few seconds - usually but not always at the bottom of the trim range.

''''''''It is possible something has happened inside the trim relay, both the up and down relay coils use the same ground.

[Harper]

Doesn't sound like a dead short. Does the motor sound like it has to strain just before the fuse blows? Sound like it slows down toward the end of its travel? Do you think it's binding at all?

[redlowrey]

Doesn't sound like a dead short. Does the motor sound like it has to strain just before the fuse blows? Sound like it slows down toward the end of its travel? Do you think it's binding at all?

''''''''The trim motor actually has a circuit breaker, so if the trim motor was pulling to much current the circuit would open, the trim motor circuit current is not in series with the relay pull in coil circuit, the trim motor would probably pull 40 amps or more. As he said it blew the fuse going up as well. I thought of the trim motor binding, it is on the 60 amp fuse line, but it does not draw current from the relay pull in coils their only function is to switch light current to heavy current in the circuit.

[redlowrey]

I should of added simple to test disconnect trim relay and run a bypass on the trim motor

[Burrhead]

Thanks for the input guys. This happened out of the blue. The trim motor sounds and operates as it always has with the exception of blowing fuses. Could you describe the bypass on the trim motor? Would I bypass the relay or trim motor?

[Burrhead]

...........or would it be a good 1st step to just replace the trim relay and see if that fixes the problem?

[Harper]

''''''''The trim motor actually has a circuit breaker, so if the trim motor was pulling to much current the circuit would open, the trim motor circuit current is not in series with the relay pull in coil circuit, the trim motor would probably pull 40 amps or more. As he said it blew the fuse going up as well. I thought of the trim motor binding, it is on the 60 amp fuse line, but it does not draw current from the relay pull in coils their only function is to switch light current to heavy current in the circuit.

Yeah, I should have gone back and reread his original post. I forgot that he's blowing the little 10A fuses.

[redlowrey]

...........or would it be a good 1st step to just replace the trim relay and see if that fixes the problem?

''''''''''See if you can replicate the problem again if so, disconnect the trim switch plug at the relay pink and light blue, make your self up a fifteen amp fuse lead and connect it to battery pos and probe the relay pins and see if you can blow the fuse again, if so fit new fuse, disconnect the trim motor plug and see if the fuse blows again.