Bilge blower question.

Galvez83

Petty Officer 1st Class
Joined
Oct 31, 2019
Messages
279
Let me start by saying i am not electrically inclined...at all. Bilge blower on a 2001 Wellcraft Martinique 2600 5.7 VP was replaced as the old one gave up. The wiring was spliced and connected to the old connector and all connected back.... Not working. Checked 12v at the plug with the switch on and 12v get to the plug. Tested blower with direct 12v and works fine. Cut the crimped plug and stripped the wires and pushed it into the plug that is at the boat side of the connector and still does not turn on. Hmmm.... tested again the plug and wires for 12v and it gets there with switch on. what could i test next. Clearly 12v get to the plug end but once connected, no juice to the blower. Fuse is fine 10amp as per the blower requirement. Any help would be appreciated i dont feel like going boom. Thanks
 

FunInDuhSun

Chief Petty Officer
Joined
Apr 25, 2010
Messages
473
So you’ve confirmed the positive side is good. Leave it connected to the blower.
Check the negative side by using a jumper directly from the negative battery terminal to the negative side of the switch.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,654
DC electricity has to travel in a circle....
+---->-
if there's no return path to the battery or neg bus bar, it won't work
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
49,546
could be corrosion or a bad connection. just enough to read on the DVM, however not actually flow any current when needed. if that is the case, verify the ground connection and power connection separately.

expanding on the suggestions above.

first, the ground. using a wire from the battery neg or the engine block, connect to the black wire on the motor. connect the other lead of the motor to the blower power feed and verify it works.

if it does, then your ground wire has an issue.

if it doesnt, switch the black wire back to the ground lead for the blower, and the positive directly to the blower. if that works, then its the positive wire from the switch that has an issue.
 

ESGWheel

Chief Petty Officer
Joined
Aug 29, 2015
Messages
469
Since I like to draw pictures, here is a visual of what Scott is talking about. Think of the connection between the blower’s wiring and the boats (the plug) as really 2 pairs of connection > the A & B and C & D in the mockup below.

Disconnect Points A & B but add a ‘test lead’ to point A that goes to a known good ground and turn on the blower (switch closed). If it runs, then “Wiring B” is bad. If does not run, reconnect Points A & B and disconnect Points C & D.

Run a test lead from Point C to a known good +12V supply (like the battery Pos post). If it runs then “Wiring D” is bad.

Fixing Wiring B is easier than fixing Wiring D but help is right here. Do this test and post the results and folks will help you thru the rest.

Also, as you get more involved in solving issues, even electrical, here is some ‘test gear’ that I have found helpful to trouble shoot. Piercing multimeter test leads > i.e., they will penetrate the wires insulation to make a reading. Example at this link. Jumper leads > small wires with alligator clips on each end > example of use is for the ‘test leads’ described above. You can make your own with some wire and alligator clips but here is an example of what you can buy link.

Blower Troubleshooting.png
 

Galvez83

Petty Officer 1st Class
Joined
Oct 31, 2019
Messages
279
Thank you everyone. The issue has been found. I checked as advised indivially, ground and switched power. Ground checked out fine. The power feed was the issue...to a degree. I was getting a weak 11v but never 12v. I traced the wire back towards the helm where the relays reside. Before the relays there is plug acting as a disconnect for the wire loom. The plug was corroded. Once the plug was moved from side to side the blower came alive. Next week i will be replacing the plug with a deutche connector. Hopefuly it will keep moisture and oxidation at bay.
 
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