R1 Mystery Wiring Solved?

Thanks to the help of WYOMIKE and mnemonic76 the electrical wiring that is unique to the R1 may now be identified. Well, you be the judge if the mystery is solved. First, let me provide a little background for those that do not remember earlier posts on the subject. Both early versions of the Renegade, R1 and R2, had a variety of options that set them apart from the CJ5. Two were the addition of an ammeter and an electrical oil pressure gauge. Consequently, small changes to the engine and main wiring harnesses were made including the addition of a resistor (similar to the ignition ballast resistor) mounted alongside the large grommet for the wiring exiting the firewall. The wiring differences largely take place at the 6-way connector in the engine compartment serving the coil, starter, etc. Even though 6 wires enter this connector on the Renegade and standard V6 CJs, 7 wires exit the Renegade only. In addition, one of the 6 wires in the bundle is different. The wire that runs from the indicating lamp on the instrument cluster to the alternator on standard CJs is replaced with a larger gauge wire that is used for the return or supply leg of the ammeter. The replacement for the alternator function above is provided by a wire that connects to the same socket in the 6-way connector as the wire leading to the ballast resistor. The added resistor mentioned earlier is spliced into this wire. I’m not real sure of the reasons why the factory did this or the logic of the circuit but it seems apparent that it was a down ‘n dirty approach to adding an ammeter by using the same 6-way connectors on hand instead of something larger with additional wires. There are other small differences in the wiring but this should shed some light on the added firewall resistor. Sorry for such a trivial and long post but the history or background on how our Jeeps were made is sometimes interesting to me.

 

thnaks guys for your efforts.
I think it's worth mentioning.
It's definitely something I'll check on a Jeep that I would be looking at.
It's another tool to help in the ID process.

 

It's possible that the resistor is a series load for the ammeter. An ammeter basically measures the voltage drop across a resistance placed in series with the charging circuit. That resistance can either be internal to the meter or external. If the gauge is under the dash, using a meter with an internal load means that all the charging current must go though the meter. By mounting the load on the firewall, small gauge wires from each end of the load can be connected to the meter, saving the expense (and hazard) of routing a high-current circuit with large gauge wires under the dash.

 

It might help to have more detail on the wires at the 6-way connector. Again, this is the connector that serves the engine functions, not the one for the exterior lights. So, here's a listing of them.

Standard CJ with V6:
1 Red (12 gauage) - Power from alternator or starter/battery
1 Gray (16 gauge) - Alternator from amp light
1 Purple (12 gauge) - Starter solenoid from ignition switch (Note: This will probably be a light blue 16 gauge wire on Prestolite starters.)
1 Light Green (14 gauge) - Ballast resistor/coil
1 Purple (16 gauge) - Oil pressure sender
1 Blue/Yellow (16 gauge) - Water temperature sender

Renegade:
2 Red (12 gauage) - Power from alternator and ammeter
1 Purple (12 gauge) - Starter solenoid from ignition switch (Note: This will probably be a light blue 16 gauge wire on Prestolite starters.)
1 Light Green (14 gauge) - Ballast resistor/coil
1 Purple (16 gauge) - Oil pressure sender
1 Blue/Yellow (16 gauge) - Water temperature sender
1 Gray (16 gauge) Taped into the female end of the connector along with the light green wire. - Alternator with 75 ohm resistor mounted on firewall

Hope this help identifying your potential Renegade.

I forgot to mention that not all standard V6 CJs will match the listing above. Carl Walck has stated to me that there were variations to the harness through the years of production. Nevertheless, it should serve to illustrate the difference well enought with the Renegade harness.

 

Thanks for the thoughts and comments Tim. That was one of the early leads I tried to chase down. However, it seems clear at this point after looking at a number of unmolested harnesses including an NOS one that the factory had the output from the alternator go directly to the ammeter and back to the starter solenoid after providing power to the light switch. I agree that it wasn't the best design. Speaking of design, I'm still confused about the 75 ohm resistor and what the factory had in mind with their layout. Any ideas besides what you've already mentioned?

 

I hope this will help.

 

Thanks Cam! That's the same setup I tried to describe above with the exception of the added green wire and single wire connectors. Question; Where does the wire on the other side of the resistor lead?