Electrical question

[dmiles452]

My marine radio (vhf) doesnt work. I have tested the incoming connection and I get 12.7 volts. If I take the connections loose and use the two wires coming out of radio and touch them to directly to one of my batteries the radio works. When I hook them up to the incoming (pos & neg) I get nothing. I am stumped

 

[dingbat]

My marine radio (vhf) doesnt work. I have tested the incoming connection and I get 12.7 volts. If I take the connections loose and use the two wires coming out of radio and touch them to directly to one of my batteries the radio works. When I hook them up to the incoming (pos & neg) I get nothing. I am stumped

What connections?
Obviously the problem is in the “connections”

You realize that voltage is only half the equation…you need current as well.

Guessing you have a bad or corroded connector

 

[mike_i]

Get a voltmeter and start tracing wires and voltage.

 

[airshot]

Had a similar issue with my new to me used boat. After tracing wires back a distance, I came across an inline fuse...yep it was bad..

 

[dmiles452]

Had a similar issue with my new to me used boat. After tracing wires back a distance, I came across an inline fuse...yep it was bad..

Ok, still confused....I have 12.7 volts at the wires the radio was connected to, but the radio does not come on. If I take the radio over to the battery and touch the two wires to pos and neg, it comes on.

 

[airshot]

Ok, still confused....I have 12.7 volts at the wires the radio was connected to, but the radio does not come on. If I take the radio over to the battery and touch the two wires to pos and neg, it comes on.

OK....that is interesting, try swapping pos and neg to see if it works...hate to say this but sure you have radio turned on ?

 

[Silvertip]

Measure the voltage with the radio connected. Folks often feel that 12 volts is 12 volts but find that it is far less or even zero when a load is applied. The problem apparently is not with the radio but with the 12 volt feed you are trying to use to power the radio. Check the ground connection (shiny clean and tight) and do the same for the positive lead. Make sure any connections along the line are also clean and tight.

 

[poconojoe]

A really bad connection or as stated....reverse polarity.

On going with reversed polarity.

Make sure that the wire that is supposed to be positive is in fact positive.

Touch the negative lead of your meter to a different negative source, like the negative battery terminal, your engine block, etc.
Then use the positive lead of the meter to probe the connector for the positive. Is the positive in the correct pin-out?

 

[froggy1150]

If you wire radio polarity backwards you have made a paperweight. Test polarity with a meter. Then check load carrying capacity with a big INCANDESCENT light like a fog light or something. 12v @ .5ma will show 12v on meter but not power anything bigger than a small led test light

 

[tpenfield]

Is there also a 'keep alive' wire? got any pictures or diagrams to share.