Re: IML: 66LeBaron-..DEAD AGAIN!

[David Whitney <hazegreen66@xxxxxxxxx>]

The problem may be hard to trace because the main battery feed wire that runs to the ammeter splits before it gets there and goes to lights and ignition.  Remember, the ammeter runs on reduced voltage.  That wire can't be "stepped up" to feed ignition.  However, a short or ground can have an impact on the other circuits fed from the same source.

 

Isolation is the key.  When you did the hotwire test, you sent 12v directly to the connector that receives 12v back from the inside of the car through the firewall.  It is fed from the ignition switch.  If you get a 12v reading at that connector, your ignition circuit is working jes' fine.  I rather doubt that it is.

 

The methodical way is to go from the four-way split to the ignition switch and backprobe if possible or remove the switch entirely if you are intrepid  If you are getting 12v into the switch but it's not coming back out, you know where the problem is.  I suspect something in there is loose or corroded, and the next suspect is the light switch.

 

But before you do any of that, be certain to check the fuses and the connectors on the periphery of the fuse box.  You may find something very interesting.  It's also a good place to probe when you're tracing circuits and checking voltage.

 

The '64 system is substantially the same as the '66, and the wiring diagrams you want are at http://www.imperialclub.com/Yr/1964/FSM/html/08-096.htm and the following page.  Trace R-6 (12 black) from its position F on the bulkhead disconnect inside the car and you see it splits four ways.  Further complicating matters, coming out of the ignition switch the ACC wire Q-2 (also 12 black) splits four more ways when you turn the key on.  As I said, isolation is the key and methodical progression will preserve your sanity.

 

You already know the starter works.  After checking the fuse box, start by locating the corresponding wire to position F (hot from battery) on the engine side of the bulkhead and backprobe for 12v.  You can also remove the connector and probe the blade (or slot, I can't remember which is which) directly.  This is the opportunity to perform the cleaning I told you about earlier.  Then move inside the car with everything connected again and backprobe position F for 12v (or disconnect and clean as recommended and probe the connector at the firewall, then reconnect and backprobe).  You're on the right road now.

 

As I said, I suspect you will find the trouble is in the ignition switch or downstream from it, manifesting itself when the key is turned.  Those wires are awfully close together and may be chafed or melted.  Don't let my suspicion stop you from performing the checks I already mentioned first, because you will be doing yourself a favor by reducing the risk of dash/engine fires.

 

Happy motoring,

David

'91 K-Imperial driver
'66 LeBaron dual air and every option known to man

---

Food fight? Enjoy some healthy debate
in the Yahoo! Answers Food & Drink Q&A.