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Author Topic: Mobile Install Question  (Read 5137 times)
K7UTA
Member

Posts: 20




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« on: July 27, 2013, 10:43:31 AM »

Not sure if this belongs in this thread or another one.
I was attempting to install a V71A in my Jeep.
Ran the wires thru the firewall, made sure I didn't snag them on the body.
Connected neg first then pos. turned radio on and nothing.
Found a blown 15 amp fuse on the power side. Replaced fuse and tried again.
Blew fuse on the neg side.
I even tried putting the radio on the fender and connecting the wires and it still blew fuses
yet the unit works perfect when connected to a power supply in the base.
What would cause the blown fuses?
Thanks for any assist.

73 K7UTA
donnie
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AA4PB
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Posts: 12843




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« Reply #1 on: July 27, 2013, 11:07:05 AM »

Have you tried it on the base power supply AFTER having the fuse problem to make sure that it still works? Its possible that if you accidentally connected the pos and neg to the battery in reverse that you blew something inside the radio that in turn is causing the fuses to blow.

Also, make sure that the radio is not being keyed with no antenna on it - that could blow a fuse.

Are the fuses blowing as soon as you connect the power or is it okay until you turn on the radio?
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K1CJS
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Posts: 6034




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« Reply #2 on: July 27, 2013, 08:32:30 PM »

How long are the mounting screws that you put the radio bracket in with?  My guess is that you've either pinched a wire or drove a screw into an electrical lead or connection.

One thing--it's very unlikely, but if the Jeep is an older one it may be a positive ground vehicle.
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K7UTA
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Posts: 20




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« Reply #3 on: July 27, 2013, 11:13:23 PM »

After the fuse blew as a mobile, I replaced it and used it on a power supply as a base with no problem.


The Jeep is an 0
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K7UTA
Member

Posts: 20




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« Reply #4 on: July 28, 2013, 06:52:45 AM »

Due to keyboard malfunction it should read Jeep is an 09
I also got to thinking that it may be a  miswired power plug.
But when connected to a power supply it works fine. Huh
« Last Edit: July 28, 2013, 07:06:55 AM by K7UTA » Logged
WX7G
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Posts: 6049




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« Reply #5 on: July 28, 2013, 09:17:51 AM »

It is wired backwards?
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M6GOM
Member

Posts: 907




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« Reply #6 on: July 29, 2013, 01:44:26 AM »

Put power wire in the Jeep. Before connecting it to the radio measure the voltage at the radio end of the cable. If it is negative you've got the leads the wrong way round.
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K7UTA
Member

Posts: 20




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« Reply #7 on: July 29, 2013, 06:46:11 AM »

I didn't think that I had miswired it.
I had checked my self a couple of times just to make sure it was right.
Ill go back and start from scratch and see if I may have made an error.
Thanks for the replies.
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KJ4OBR
Member

Posts: 104




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« Reply #8 on: July 29, 2013, 12:44:57 PM »

You have a short somewhere. Check the wires for breaks in the insulation. I'd start from the point the wires cross the firewall and examine closely under the hood, then do the same in the cabin.  You could also just pull the wires and visually check them. I'd replace them if there was any hint of a bad spot. At the danger of sparking a "firestorm" of opinion, you are running + and - directly to the battery right?

Dave


Not sure if this belongs in this thread or another one.
I was attempting to install a V71A in my Jeep.
Ran the wires thru the firewall, made sure I didn't snag them on the body.
Connected neg first then pos. turned radio on and nothing.
Found a blown 15 amp fuse on the power side. Replaced fuse and tried again.
Blew fuse on the neg side.
I even tried putting the radio on the fender and connecting the wires and it still blew fuses
yet the unit works perfect when connected to a power supply in the base.
What would cause the blown fuses?
Thanks for any assist.

73 K7UTA
donnie
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APW19562
Member

Posts: 46




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« Reply #9 on: July 29, 2013, 07:24:54 PM »

This may be a longshot... but check to be sure you don't have a bad alternator. When my Expedition alternator goes bad, it starts leaking AC voltage into the electrical system. Had this happen twice now already.
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K7UTA
Member

Posts: 20




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« Reply #10 on: July 30, 2013, 06:45:54 AM »

Dave, Yes the cables are run to the battery.
After I got frustrated and remeved the wires,
 I checked them for breaks and found them to be free of any.
Bad part is the wires in question are the ones that came with the radio.
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K1CJS
Member

Posts: 6034




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« Reply #11 on: July 30, 2013, 04:03:23 PM »

Something else to check is the condition of the battery cables themselves.  Could be that the cables are corroded or have weak connections, and the negative current from the battery is finding an easier way through the rig wiring then the negative cable.  Could well be too that a ground strap has been disconnected somewhere.

On an aside and without trying to sound like a wise guy, are you sure you connected the rig wires correctly at the battery and didn't accidentally mistake the polarity?  It's all too easy to do.  73!
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N2MG
Administrator

Posts: 123



« Reply #12 on: July 31, 2013, 06:21:56 AM »

You need to divide-and-conquer. 

a) Disconnect the power cable at both ends (from battery and from radio). With good fuses installed, measure between the pos and neg sides and be sure that they aren't shorted.  Do this at both ends of the cable.  Then check for continuity through each side of the cable.  That's 4 measurements.

b) If the cable is no longer "thru-the-firewall"  routing why not just hook it up to your battery and radio see if it operates and doesn't blow a fuse?

c) If/Once installed through the firewall (but not hooked up to anything at either end!) run the same 4 tests as in (a) plus 2 more tests - measure both sides to vehicle ground.

Please note when checking for connections (shorts) to "ground" in a car, not all "grounds" are created equal. Many seemingly grounded chassis parts are poor (ohmic) grounds - especially when plated, oxidized or covered in road/engine films/grime.  Probably best to use the battery terminal unless you are sure that screw or bolt you are assuming is ground is really ground.
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K7UTA
Member

Posts: 20




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« Reply #13 on: July 31, 2013, 06:58:29 AM »

In answer to the previous post,  I have already tried "b"
suggestion and had the same results as when the wiring was in the
Jeep. Only the fuse on hte Neg side blew.
Thats when I pulled everything out and figured Id try it again later.
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N2MG
Administrator

Posts: 123



« Reply #14 on: July 31, 2013, 07:05:24 AM »

Did you try it (b) without a radio hooked up?
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