[CW4B]

Originally Posted by VetteVet

I'm your Huckleberry.



CONDITIONS
Battery disconnected
Starter disconnected
Ignition Switch disconnected

KEY
SOL=Purple to starter S Check

G2=2 brown wires for brake warn light Check
IGN=Pink to power HEI The pink wire runs to a tee and powers the Ignition, The key on fuse panel circuits, and from there to the dash cluster for power to the fuel and temp gauges.


ACC=1 brown + 1 brown with white stripe to accessory on fuse box. The large 12 gauge brown wire is the accessory wire to the fuse panel but the smaller brown /white stripe wire is the alternator exciter wire that runs to the firewall block on the inside of the cab and from there on the other side it becomes the 16 gauge brown wire to the external voltage regulator. The smaller brown/white stripe is a special wire that incorporates a resistor valued at 10 ohms to match the 10 ohms for the light cluster. It was used by the factory to failsafe the alternator in case the idiot light bulb blew. They just kept it for the trucks that had the gauge dashes without the charging light.


BATT=Red wire to battery (not sure if this actually goes to battery) This wire runs from the ignition switch to a tee with three other red wires that feed the fuse panel for key off power, the headlight switch, the horn relay, and the main one which goes through the firewall block to the main soldered junction with the alternator, battery, and regulator wires. Actually the flow is reversed from the battery and alternator soldered junction into the cab.so indirectly it goes to the battery

CHASSIS GROUND=not a wire but chassis ground Check

MEASURES
Are these measures just on the key switch or the wires in the key switch plug.? If just the key switch to ground I don't think there should be any resistance between any terminals and ground with the key off.
CHASSIS GROUND-SOL=infinity check
CHASSIS GROUND-G2=127 ohm I'm pretty sure this won't hurt but when key is turned to SOL it should be near zero ohms to gnd. It grounds the brake warning light during start to check the bulb. The other green wires in my picture do the same thing but for the temperature light in the light dashes.
CHASSIS GROUND-IGN=122 ohm I would not like any reading here, this should not be any connection to ground with key on or off. If the harness plug was plugged into the key switch and the key was on, you might see some resistance to ground through the ignition coil.


CHASSIS GROUND-ACC=6K ohm This is enough to prevent a short to ground but infinity would be better.

CHASSIS GROUND-BATT=7.6M ohm same here, This is almost infinity


Are these on the harness plug wires or between the key switch terminals? I'm assuming it's between the key switch terminals.
SOL-ALL=infinity With key off or not in start position, yes
G2-IGN=12 ohm If this is the brake warning light terminal there should be infinity otherwise the ignition would be grounded and the battery and accessory wire would be grounded when the key was in run or start


G2-ACC=6K ohm I am not comfortable with this even tho it's a lot of resistance I think it should be more. Check it with the key in SOL(start) you should get near zero ohms.


G2-BATT=infinity Yes, the BATT wire is 12 volts hot all the time and should not be closed to G-2 with any resistance. Remember G-2 is connected to gnd when the key is in SOL
IGN-ACC=6K ohm That's enough to keep the battery from draining but it should be near zero with the key in run.

IGN-BATT=infinity key off yes, key on near zero
ACC-BATT=infinity Same

Should I be concerned about any of these readings?


I think I misread your post and you were talking about the wires in the ignition switch plug so I'll comment on them.



MEASURES
CHASSIS GROUND-SOL=infinity Check
CHASSIS GROUND-G2=127 ohm check


CHASSIS GROUND-IGN=122 ohm I believe this reading is OK because you are reading the wiring resistance through the light to ground.

CHASSIS GROUND-ACC=6K ohm This is OK as well because all the resistance to loads are switched, If the switches are off you have no path to ground. Try turning on the wiper switch, and the heater switch and then the turn signal switch and watch the resistance decrease.


CHASSIS GROUND-BATT=7.6M ohm This is OK because 12 volts would not push through this much resistance unless it was in the milliohms scale.

SOL-ALL=infinity no connection to any of the other wires but you might see some to ground, reading through the solenoid windings, I'd guess near 200 ohms

G2-IGN=12 ohm This is about right, remember the pink wire feeds the cluster panel and posers the brake warning light so you're reading the light bulb resistance between the pink and brown G-2 wires wires

G2-ACC=6K ohm Yeah no connection between the BW light and the accessory until the key switch is in run and then the light is not grounded unless the BW switch is grounded or the key is turned to SOL.

G2-BATT=infinity Pretty much the same as G-2 to ACC.
IGN-ACC=6K ohm Reading through the fuse panel and cluster feed circuits but not enough to hurt anything .


IGN-BATT=infinity None here is good no battery drain unless the key is on or in ACC
ACC-BATT=infinity Sameo sameo

Should I be concerned about any of these readings?

I don't think so but proceed with caution.


leave your battery disconnected until you have all the wiring connected and the key switch is off. Then test the battery for current flow by tapping the terminal to the negative post and look for any spark. or test for a key off drain. If you get less than 50 milliohms between the negative terminal and the negative battery cable, you don't have a short in the key off circuits. You will get more than that if you have any lights or switches turned on so be sure every thing is off.

With the key on and the negative battery cable disconnected, tap the cable on the battery and you will see some spark but not much if all the switches are off , and the doors are closed, radio is off etc.
You can't use the multimeter because it's amps reading is limited to 10 amps and you might exceed that and harm the meter.

Most everything else is fused so if any shorts to ground it will blow fuses.

That's about all I got!

Can't thank you enough for such a thorough response. This is study material that's making the wiring diagram I've been studying and the wire tracing I've been doing make more sense.

I didn't clarify well, but I was conveying measures taken on the wires only - not the ig sw. Chassis ground to each one and then each one to each other.

I pulled the purple SOL and yellow R (to non-existent coil) all the way out to the firewall, separated and then rerouted the purple SOL wire back to starter. The yellow R wire had been spliced to the resistance wire that goes into the fire wall with another spliced yellow wire that went down to the passenger side of the engine, crossed over to the driver's side between the engine and transmission and then dangled there but connected to nothing. This second yellow wire was wrapped with a green one that connected to a temperature sensor on the driver's side of the block. Very circuitous route for the green wire given that it went into the firewall on the drive's side as well. Not sure if that was factory looped around for resistance reasons or someone was having bad day when they installed it under a shade tree?

I plan to wait until after I get her running again before I cut anything, but I think I can simply cut that yellow R and the resistor wire going into the driver's side firewall out of there completely. Don't think it is needed with the HEI.

The spark test method at the battery is brilliant. Now I can wade into this and possibly avoid another smoke fest if there still is something else wrong.

Thanks Vettevet