Engine Wiring Harness - Missing Wire

[mwesten]

Hey all - I?m process of brining 10187 back to life. Cleaning out engine bay and noticed this wire (seems to be brown, so power?) missing. Not sure if prior owner cut it off or if it just rotted off in-place. Anyone know what this wire does? OCD part of me wants to repair it either way.

69426

[WHO1DMC]

Hey all - I?m process of brining 10187 back to life. Cleaning out engine bay and noticed this wire (seems to be brown, so power?) missing. Not sure if prior owner cut it off or if it just rotted off in-place. Anyone know what this wire does? OCD part of me wants to repair it either way.

69426

That has to be one of the original alternator wires. The original Ducellier alternator needs two wires brown and brown with yellow stripe. Then they went to Motorola or owners went with a some other possibly GM based alternator the brown wire is no longer needed.
I was working on my wiring harness last year so I totally removed the entire wire.
Mine was cut at the alternator apparently they cut it there.




Dave B.

[Michael]

Yes that is the signal wire to the OE alternator. That just means it was cut correctly according to the TSB rather than leave it live and 17 years later grounding out and melting the harness like my DMCH refurb (restored by "professionals so you know it's been done right") did me.

[mwesten]

Yikes ok glad I asked thanks fellas. Thought it was weird a small section of the wire just fell off lol.. but then again it?s a Delorean so never know. I def have the Motorola? plan on replacing it after I get the fuel lines done.

[81dmc]

It's actually a good idea to reconnect that wire if you have the newer GM alternator. Connect it to the S terminal and the battery light will no longer flash and the alt will respond better to load changes.


Mine charges at 14.6 volts with it connected.

[WHO1DMC]

It's actually a good idea to reconnect that wire if you have the newer GM alternator. Connect it to the S terminal and the battery light will no longer flash and the alt will respond better to load changes.


Mine charges at 14.6 volts with it connected.

Can you clarify by newer. The alternator on mine has been there since 2014. Doing about the same voltage no blinking light and has the one wire.


Just curious on the alternator is it from DMCH? Do you have the model number?



Dave B.

[81dmc]

Can you clarify by newer. The alternator on mine has been there since 2014. Doing about the same voltage no blinking light and has the one wire.


Just curious on the alternator is it from DMCH? Do you have the model number?



Dave B.
I first reconnected it when I had a DMCH alternator. Since then I went to a Camaro alternator for my 3.0 and it's the same,

For full charging voltage on GM alternators, they need the S Sense wire.

[WHO1DMC]

https://dmctalk.org/showthread.php?12181-DMCH-alternator


Electrical Best replacement alternator?
https://dmctalk.org/showthread.php?15708-Best-replacement-alternator&highlight=John+Hervey+alternator

Whent looking for information and found it. There is definitely a lot of information on this subject.
And with the solutions that are in these threads you don't necessarily need the brown wire from the bulkhead.


Dave B.

[81dmc]

https://dmctalk.org/showthread.php?12181-DMCH-alternator


Electrical Best replacement alternator?
https://dmctalk.org/showthread.php?15708-Best-replacement-alternator&highlight=John+Hervey+alternator

Whent looking for information and found it. There is definitely a lot of information on this subject.
And with the solutions that are in these threads you don't necessarily need the brown wire from the bulkhead.


Dave B.
You don't NEED it, but it's better as you are sensing voltage in the fuse/relay compartment vs at engine.

Power in fuse relay compartment on mine is 14.2 or so, but at engine, it's 14.6-14.7. This voltage compensation helps immensely with radiator fans, headlights, AC blower, etc.