Aux Wire Dead - Fuse not Blown

[Richard L. Willy]

I had my my President Adams CB and Midland MTX575 both wired to the 10 amp constant on battery AUX wire (Fuse F72) i believe. the wire is dead with no voltage. The CB works when wired to another AUX wire. the Midland is dead even when wired directly to battery. None of the 5 fuses (1 on jeep, one one CB or the 3 on the midland) were blown. have yall ever heard of this before?

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[swampflyer]

I had my my President Adams CB and Midland MTX575 both wired to the 10 amp constant on battery AUX wire (Fuse F72) i believe. the wire is dead with no voltage. The CB works when wired to another AUX wire. the Midland is dead even when wired directly to battery. None of the 5 fuses (1 on jeep, one one CB or the 3 on the midland) were blown. have yall ever heard of this before?

Bad radio maybe?

 

[Beachcomber72]

I had my my President Adams CB and Midland MTX575 both wired to the 10 amp constant on battery AUX wire (Fuse F72) i believe. the wire is dead with no voltage. The CB works when wired to another AUX wire. the Midland is dead even when wired directly to battery. None of the 5 fuses (1 on jeep, one one CB or the 3 on the midland) were blown. have yall ever heard of this before?

Make sure that switch # is activated in the AUX menu on the head unit.

 

[Richard L. Willy]

Bad radio maybe?

The radio definitely has an issue. its dead. but so is the Aux wire.

 

[Richard L. Willy]

Make sure that switch # is activated in the AUX menu on the head unit.

There is no switch for this wire. there are four switches and six wires. four go to the switches, one goes to battery for power the last is an ignition on wire.

 

[Beachcomber72]

There is no switch for this wire. there are four switches and six wires. four go to the switches, one goes to battery for power the last is an ignition on wire.

@Rhinebeck01

 

[GATORB8]

I don't even see a splice in that wire on the diagram.

Anything happen or get installed around the same time?

I guess there's the potential that there was a positive backfeed on the ground terminal that grounded to the antenna.

I'd test continuity from F72 output to the wire output, and see if it's cut/broken.

 

[swampflyer]

There is no switch for this wire. there are four switches and six wires. four go to the switches, one goes to battery for power the last is an ignition on wire.

sounds like maybe a break in the wire?

 

[Rhinebeck01]

@Rhinebeck01

I saw the OP's post.

I don't even see a splice in that wire on the diagram.

Anything happen or get installed around the same time?

I guess there's the potential that there was a positive backfeed on the ground terminal that grounded to the antenna.

I'd test continuity from F72 output to the wire output, and see if it's cut/broken.

Yup.... I agree with this post.

OP, also as stupid as it sounds first try a different 10 amp fuse in F72. Could be that 10 amp in there is not healthy..

 

[Richard L. Willy]

I don't even see a splice in that wire on the diagram.

Anything happen or get installed around the same time?

I guess there's the potential that there was a positive backfeed on the ground terminal that grounded to the antenna.

I'd test continuity from F72 output to the wire output, and see if it's cut/broken.

CB was installed for almost a year, worked no problem. I recently installed my midland, probably should have used a 40amp wire, but it worked great the first half of the day. testing for continunity, which part of the fuse holder am i checking on F72?

 

[Richard L. Willy]

I saw the OP's post.



Yup.... I agree with this post.

OP, also as stupid as it sounds try a different 10 amp fuse in F72. Could be that 10 amp in there is not healthy..

How does a Positive backfeed on ground terminal happen, and, more importantly how do i avoid in the future.

Jeep is at dealer at the moment for oil change and recalls, i'll check this later this week.

 

[Beachcomber72]

CB was installed for almost a year, worked no problem. I recently installed my midland, probably should have used a 40amp wire, but it worked great the first half of the day. testing for continunity, which part of the fuse holder am i checking on F72?

This is definitely more sounding like a bad fuse in the circuit.

 

[Rhinebeck01]

How does a Positive backfeed on ground terminal happen, and, more importantly how do i avoid in the future.

Jeep is at dealer at the moment for oil change and recalls, i'll check this later this week.

With your install... did you have both pos and ground fuse protected?

I myself fairly recently learned it is best with such goodies as you installed to fuse protect both the ground and the positive wire...

....."negative lead is fused because of the possibility of a faulty ground elsewhere in the vehicle, which could cause excessive current to flow in the negative lead to the radio. " which will kill the radio and...

Read here:
https://ham.stackexchange.com/questions/6580/why-do-some-radios-have-two-fuses-in-the-power-leads

 

[Richard L. Willy]

This is definitely more sounding like a bad fuse in the circuit.

can fuses be bad without being broken? all five were tested for continuity and all passed.

 

[Beachcomber72]

can fuses be bad without being broken? all five were tested for continuity and all passed.

Technically yes, but while not common it’s also not that uncommon. Also if I remember correctly isn’t there a separate block of fuses/relays independent from the main PDC?

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