Questions:

1) could towing a friend's trailer have damaged my multifunction switch? Why? Should I worry about towing my boat in future?

2) Is there a proper diagnosis for bad mfs? I have no brakelights, bulbs good, fuses good, and mechanic friend believes it's the mfs, but electrical is not his strength. The part price new from dealer is $200+, labor $160. From reading past threads, it seems it could be a variety of possible problems, from bad wiring/rear ground, rear sensor, etc. That's why I'm wondering if there is an exact diagnosis for bad mfs involving only no brakelights.

Any suggestions appreciated.

Steve in ATL

 

download the factory service manual from the faq section here. That will have wiring diagrams that will point you in the right direction. Do your turn signals work??

 

@HeyYou,

Belated thanks. It was the multifunction switch, got it fixed, all good.

Still wondering if towing a friend's trailer might have caused the failure. I'm getting my boat ready for use and I'm a little gun shy to hook up the lights. Might this have caused the failure? Is there a way to check my trailer light plug to determine if the problem is in my rear plug?

 

Never saw something like this damage the mfs. But I would certainly double check the wiring at the rear to make sure something isn't cross wired. This could generate all sorts of evil gremlins. Also, double check wiring on trailer.

 

Do you have tilt steering? A trailer plug should not have any effect on the mfs.

Just a tip unplug the boat trailer wiring plug before you back into the water.

 

Ask him how he knows that.