radio power wire damage

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L.Tigre
Posts: 50
Joined: Fri Jul 22, 2022 3:53 pm
Location: Greenville SC

radio power wire damage

Post by L.Tigre »

In a flashback to my teenage years, I attempted to install a Blaupunkt Bremen stereo in place of the stock head unit on my '87 635csi. The wiring on this is somewhat complex as you may know. And it just got more complex...

For whilst troubleshooting some power issues, I heard a faint crackle and saw a wisp of smoke rise, and then heard the snap of a fuse. Somehow in my rats nest of wires, power and ground got crossed up and the 30A radio fuse burned out.

No worries, I replaced it easily. But... now the radio does not come on at all, even when re-hooked to the same power+ground wires it did before. I tried multiple options, no dice.

And then, thinking maybe I damaged the new unit, I attached the radio straight to battery. And there, it does seem to work just fine.

Therefore: seems I have damaged something in the wiring harness heading between the power distribution box and the radio. Any suggestions what it might be? Is there an inline fuse somewhere that I'm not seeing? Just as important: is there a line somewheres similar to KL30 (always hot) and KL15 (hot when ignition is on)? I have reviewed the radio wiring diagram in depth and tested; I can 100% confirm that the ignition related wire (what I would call KL15; a purple and white wire) caries no power. Am I missing something? or, is maybe this wire also damaged someplace?

Depending on your feedback I may need suggestions how to re-build or re-purpose a power circuit to get this thing going. I am stuck and the moment...

Thanks in advance for any help...
Jlc
Posts: 287
Joined: Sun Sep 27, 2020 5:27 pm
Location: Atl

Re: radio power wire damage

Post by Jlc »

I would trace the KL15 back to the ignition switch or connection point and use an ohm meter to check continuity. If it is an open circuit then teh wire is bad and you could run a new one. I assume you've checked fuse 21 and 12?
85 635CSi Bronzit
Jubilados
Posts: 161
Joined: Sun Mar 08, 2020 4:48 am
Location: So Cal

Re: radio power wire damage

Post by Jubilados »

You should always have a basic $5 12v test light when working on electrical.
As Jlc stated, the first place to check is the fuse box.
Since you were getting power, and lost it instantly, that’s a likely source.
If not, using a continuity tester of your choice, test the wires starting at the fuse box and see where power drops off.
(Also the Bremen wiring is no more complex than any other radio, it’s completely standard).
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