63/64 Ignition Switch Testing

[Erv M.]

Re: 63/64 Ignition Switch Testing

Erv, This is getting even more strange...

Please remove IGN switch from harness and do the same test at the harness plug with jumpers. With Red=Pink, Tan=Gnd. Should light up.

It seems you IGN switch is intermittent. May want to repeat that IGN switch bench test again, several times.

PS my laptop just died so forgive spelling errors on my phone...

Removed IGN switch from harness and jumped RED to PINK and had an instant light. Rechecked the ignition several times and all checked out.

Then I reconnected the IGN to the harness and checked the RED for 12v, no power. Removed the connector and checked the RED it had 12v. What would cause the red to lose 12v power when connector to the ignition?

[Richard M.]

Re: 63/64 Ignition Switch Testing

Removed IGN switch from harness and jumped RED to PINK and had an instant light. Rechecked the ignition several times and all checked out.

Then I reconnected the IGN to the harness and checked the RED for 12v, no power. Removed the connector and checked the RED it had 12v. What would cause the red to lose 12v power when connector to the ignition?

Getting even more strange.......

What is your source of 12V ? A Battery? A Power supply? Is your source going to the Fuse Panel POWER WINDOWS terminal? Do you have a Circuit breaker attached to it? Check Cluster Ground also.

.... I'm sending you a email via the PM system with my cell#. Give a call. I'm in Florida, EST.

Rich

[Erv M.]

Re: 63/64 Ignition Switch Testing

Getting even more strange.......

What is your source of 12V ? A Battery? A Power supply? Is your source going to the Fuse Panel POWER WINDOWS terminal? Do you have a Circuit breaker attached to it? Check Cluster Ground also.

.... I'm sending you a email via the PM system with my cell#. Give a call. I'm in Florida, EST.

Rich

Power source is from my car battery with 14 gauge jumpers through the fuse panel attached to the BAT POWER tab. I have been using a test light utilizing the ground so I am confident the ground is good.

[Erv M.]

Re: 63/64 Ignition Switch Testing

When connecting the connector to the IGN when the ACC makes contact the light goes off

[Erv M.]

Re: 63/64 Ignition Switch Testing

A conclusion to this saga.

First let me thank Richard Mozzetta for walking me through a very thorough diagnostic of my cluster instruments and new wiring harness. It was quite baffling as 12v were present at the BAT terminal on the ignition with the connector installed and once the key was turned to run it dropped to zero. Basically it demonstrated a short. The ignition switch was tested with a light than meter and all was good. Pulled all the fuses, no help. Finally the culprit was exposed when Richard started to probe to the glove box light and connections that pass through the firewall.

In my attempt to be ready to reinstall the cluster I removed all the connectors from the engine run harness so they would fit in the new grommet I had installed in the firewall. I made sure I documented with photos so I could reinstall the connectors. Even better I tied each set of wire together and tagged for future reference. Not very smart of me as the brown wires were unprotected and touching thus creating the short we traced for too long.

Again, special thank to Richard for helping me with this frustrating endeavor.

Erv

[Richard M.]

Re: 63/64 Ignition Switch Testing

Glad we figured it out Erv.

As a point of interest to all, I'd like to mention the importance of using some form of fuse protection at the battery source when bench testing a Cluster. Luckily in Erv's case the short was on the Brown(ACC) wire at the end of the harness for the Wiper Motor. It must have been a slight connection short to Ground, not a hard short. If so a long bench test duration could have done much harm. A 15 Amp fuse or circuit breaker between the battery +12v source and the cluster bench test is good insurance.

For reference, the key to diagnose this odd fault was that whenever the IGN switch was in RUN, the fault occurred. The fault manifested itself while testing the Park Brake Lamp circuit while activated by grounding the negative lamp socket input(Tan). Key to RUN, no lamp. Key to START, lamp lit properly.

When key = START, power is applied to the Ignition circuits to the Ballast/Coil+, Fuel/Temp Gauges, Fuel Sender, Backup Lamps, Park brake Lamp, etc along with Solenoid power to the starter. While in START, the ACC circuits are disabled, i.e. Radio, Heater, Wipers. When the key is returned from START to RUN, ACC circuits are then reconnected to power. The actual key ACC position(fully CCW), powers only those accessory circuits with no power to the ignition circuits.

Simply, the Park brake lamp lit when ACC was disabled(START). Lamp failed when in RUN because ACC was shorted to Ground. Once the short was cleared the lamp lit in RUN.

Rich