350350

We got the boy a '95 Z28 project car so we don't know much about its history. It's got a weird issue with I believe the steering column.

The air bag and security dash lights stay on all the time, and I had to disconnect the cable that keeps you from taking it out of park. I'm assuming that is related to the security issue.

Anyone familiar with something inside the column that causes this? I was thinking of just putting a different column in it but I don't know if that's going to mesh with the existing alarm and BCM.

I read on another forum that there's a single wire in the column that breaks inside the harness, and causes this problem. But that post didn't give much detail about which wire or where it breaks. I don't want to tear the entire column apart based on just that one post.

I have no idea where to even start troubleshooting. ?

GaryDoug

You can start with the air bag light by checking the SIR (supplemental inflatable restraints) trouble codes. Download the free 93 service manual here: https://www.mediafire.com/?40mfgeoe4ctti
Then read the section on how to flash the air bag trouble codes at the front of the SIR section. I suspect the cause is a broken "clock-spring" cable, in the steering column, for the driver side air bag.

Also flash the engine trouble codes and see if one refers to the security lamp issue (DTC46). That may be caused by a defective key cylinder contact in the column.

shoebox

The park/lock cable has nothing to do with the security light that I know of.

350350

Thanks I'll start there. It doesn't currently have any engine trouble codes at all. I'll read up on the SIR stuff and report back.

350350

What does operate the other end of the park/lock cable? Is it a mechanical linkage to the brake or the ignition cylinder or something? I guess, how is it supposed to work?

Injuneer

Looking at the 94 factory manual, the park lock cable appears to be purely mechanical. Clips into a bracket on the side of the steering column about midway, in the 10 o'clock position, and into the shifter base. The cable appears to extend into the column to stop the ignition switch rod from moving into the off position until the shifter is in Park.

There is another system that is electrical, which prevents you from moving the shifter out of Park unless you have your foot on the brake. Is that what you disconnected? I don't think that is connected to the PASS-Key system.

With regard to the replacement of the column, the 95 does not have a BCM.

350350

The one I disconnected was the one that keeps you from taking the shifter out of park unless you have your foot on the brake. It was not letting me take it out of park under any circumstances... running or not, key on or off, brake planted firmly or not, etc. What electrical event is supposed to trigger its release?

So I can just swap in a new column as long as I have the right ignition key? Is there any other reason I'd need to retain the car's original pass-key chip key?

GaryDoug

One of the switches on the brake pedal lever operates a solenoid attached to the shifter. Either could be defective. That cable is electrical, not mechanical. The mechanical one is for the key cylinder control, to block the key from turning when not in park.

You need to have the same resistor pellet value in the new key so that it matches the value programmed into the TDM (theft deterrent module). So you would measure the old key's resistance, buy a new blank key (about $10 on ebay) with the same resistance (1 of 15 values) , and have the new blank cut to match the new column's key.

Injuneer

Without looking at the schematic, I suspect the brake switch for the foot-on-the-brake solenoid gets power from a switched ignition source. They wouldn't want a kid with his foot on the brake (key not in ignition) to be able to take the trans selector out of PARK.

The SECURITY light will stay on if the wire from the ignition cylinder resistor contacts to the TDM is open.

Both problems can possibly be related to the wiring in the column.

shbox.com has "how to" for ignition switch replacement, steering column replacement and PASS-Key2 problems. Worth a look.