Hi, PM your email and I can send you some material that may help.

 

I also have a 1987 Sundance. Wiring diagrams could help a lot. Any ideas where to find them

 

When I installed my new gauges, I got them straight from the Faria website. Not sure what gauges you have, but you might want to try there. On mine, the sender location was marked on the back with an "S", positive was marked "Batt" or "+" and Ground marked "G" or "-". the gauge lamps shared the ground and the lamp was not a post, but a spade, I believe typically blue.

 

Black ground (Daisy Chained Across All gauges)
Purple (12VDC positive) (To most gauges)
Pink (Fuel Sender)
Baby Blue (12VDC Positive gauge lighting (Daisy Chained))
Gray (Tach)
Tan (Trim Sender)

 

In 1987 all boat wiring followed a protocol established by the American Boat & Yacht Council (ABYC). What Blew By You wrote is correct but if you want a bit more detail do a search for ABYC Wiring Standard. In fact, I just did it for you.
https://www.bing.com/images/search?q=abyc+wiring+diagrams&qpvt=abyc+wiring+diagrams&FORM=IGRE
What you are looking for is in these pics.

 

huh... my tan wire is the cylinder head temp sender

 

You have an outboard motor. Engine wiring is a bit different than inboard engines.

 

excellent point.

BTW, I lowered the transducer a half inch, next time I go out I'll see if that takes care of the depth gauge giving no reading at "high" speed.

 

My bad, you are right...tan should be temp. Trim is Brown w/White stripe.

 

I also am having a Dash wiring issue with my 1988 Sorrento s24. I am looking for a diagram to help me troubleshoot. Engine wiring is fine, all gauges work, yet none of the dash lights, switches, bilge pump switches, Horn, etc... are working. The previous owner has done some "creative Engineering" and I am going to need a little help figuring out what I need and what I done.
Thanks for listening.