Very strange electrical happenings 1979 43 DC

O.K. odd things happening here, firstly, the bilge blower circuit from the Cb went u.s. so, ran new wire from cb to fuse block, now the only way to get the blowers to operate is turn on the cb, dash switch does not operate any more...

Today, the centre bilge pump, the one beside the master shower tray pump, gave up, checked the pump, float sw, all ok, there is no dedicated cb for this pump, maybe a fuse,,but all fuses are ok, the terminal block where all the wires connect, there is no 13 v, so I jumpered a 12 v circuit and the pump works fine.

Is it possible that the wiring is actually failing ? when I did a continuity test on wire from the cb to the blower fuses it was toast and it's only 28 " long, now the final connection terminals may be faulty but that is very odd indeed. the wiring on the boat looks first class, clean, corrosion free. ( visibly),so it is frustrating, I do not like having to jury rig on a permanent basis, and, access is not the easiest for extended testing. any one else seen this type of issue happen ??

Check the bilge blower switch to see if it's ok, the contacts could be stuck on, if it is OK recheck your wiring.

Maybe there is a fuse on the back side of the CB panel for the bilge pump or maybe the breaker is mislabeled? somewhere there should be protection.

I would start with thinking that most of your wiring is OK as you indicated it looks nice and neat. Look for junction boxes and terminal ends, tug roughly on the crimps to see if they are loose, tighten as many terminal screws as you can everywhere and clean whatever you can get to, make a project out of it and take you're time. A good tune up on the wiring is time well spent because you really learn the system and understand it better, you may eliminate existing & potential problems as well. Cleaning fuses & fuse holders with green scrubby pads/wire brush/fine sandpaper and blocks, making sure that fuse holders have a good squeeze will prevent some fuse failures.
I know it's not pleasure boating but it will improve the chance of enjoying some!

Good Luck,
Geo

The circuits usually give trouble at the ends, not in the middle of the wire, unless something is leaning on it, chafing it, or stretching it. Usually the ends and connectors corrode and go bad. If you have to cut the wires back and install new ends, a little CopperShield on the wire strands before you crimp the new connector on seems to help. Electrical supply houses have it, in a little jar like AntiSeize.

As far as the blower sw goes, there is no voltage on either of its contacts, yet the blowers come on when the CB is active. So that is a real puzzle, worked ok last year.

The bilge pump issue is just as puzzling, there seems no connection point for the 12 v supply, the wiring diags, show no cb for centre bilge, but references a connection point to a distribution panel in the E/R, actually I believe that panel is in the hanging locker , master s/r, has about 75 connection points in there, all fuses are showing 13 v ea side. the wire that would be carrying the 13v to the remote dash sw is so short at the sw location I cannot strip it back, am going to see if I can pierce it with a needle just before the connector and check voltage that way.

Still no luck tracing the negative wires from the port and stb'd running lights, they are black and just vanish and could come out anywhere, may have to pull new ones.

Thanks for the suggestions.

dennis, on your blower problem, the switch is probably between the c b and the fuse. you said you ran a new wire from the c b to the fuse, which would bypass the switch

Yes Bill, but, when I checked the fuses first, they were "dead" traced the source back to the CB and that is where the problem was, replaced the wire, and the fuses became hot, there is one fuse for ea blower, so I assume that the fuse then sends 13v to the dash sw, which then turns on the blowers.

Your scenario makes sense but as I said the wire from the cb goes directly to fuse block, 30 " away, I need to buy one of those electronic line finders, have on on my boat in Vancouver must get one for here then I can find those wires a lot easier