I trying to troubleshoot my sister-in-law's '96 Mazda 626 LX automatic. When it runs, everything is ok. Currently it is starting and running ok. My SIL is afraid to pick the car up from the garage because it has failed her twice in three days. When it fails the only thing that works is the headlights. The key will rotate to start, but there is no radio, no dash lights, no starter, no sounds at all, the transmission is locked in PARK and the steering wheel will not turn. I don't have a manual for the car so I can't look at how the ignition key works. Many years ago, I helped a friend with an old Mercury with the ignition key on the steering column where the linkage between the ignition key and the actual switch was so worn that though the key was rotated the switch never closed. Would someone with a shop manual look at a drawing of the ignition switch and determine if there is something like a tab or linkage on the lock that could be worn down enough to allow the key to rotate without unlocking the steering wheel?

Thank You

 

There is no linkage on the ignition switch. I know what you are talking about though on American cars. The switch is attached behind the lock cylinder.

Do you know if the other systems like brake lights and dome light that normally work with the key off still work, or just the headlights? Does everything seem to work but all goes dead when trying to start the car? It almost sounds like a bad connection in the battery cables somewhere. If the battery ever leaked in the past and corroded the cables, it can take many years to manifest itself in the future with the corrosion internally in the insulation of the cable.

 

The head lights and brake lights will work when the failure occurs. This is the third time in a year that this failure happened. It always occurs when the car has been turned off. The length of time it has been turned off doesn't seem to matter. The first time, several months ago, occured when it sat overnight. The second time last Thursday it had been off about five minutes. The last time was after it was off for about four hours. The last time, several people and a AAA assistance driver tried to start it for about four hours. Nothing helped and the car was towed to a garage and left there overnight. The next morning, it started with no difficulty and has continued to start Monday and Tuesday at the shop. Whatever is happening causes no voltage to the starting circuit or any accessories. It has never happened when the car was running. When it doesn't work, there is no sound at all, no click or clicking, no dash lights, no radio. The first two times, repeatedly switching from locked to start and back to locked eventually cleared the problem. It did take a lot more switching the second time. Each time, it would not start, She tried it with the brake depressed and not depressed. She tried shifting from PARK and back to try closing any safety that might be in the transmission but the shift was locked in PARK. They tried rocking the car to set the parking pawl in case it does have one and the parking pawl hadn't clicked into park. Since, you say there is no mechanical linkage between the key and the switch, I am leaning toward having the mechanic remove the key mechanism and inspect it and the surface it turns for wear and then I guess we will have to remove the ignition switch. The wiring diagram I found online indicates that the switch has two waffers but it did not indicate which accessories were on which waffer. Do you know if there is a firewall connection that the battery voltage must pass through before getting to the dash? Would that same connector carry the voltage for the headlights? I live too far away from her to do any troubleshooting for her.

 

I finally found an illustration with instructions for removal and testing of the ignition switch. There wasn't anything to indicate that the core could be removed by itself and the illustration looks like the switch and lock core are replaced as a unit. I hope the mechanic finds something else simple, but it doesn't look good. I'll try talking him into unplugging the ignition switch plug and replugging it. But, until it fails for him, he probably won't start on something like that. If you have any other thoughts, I'd love to hear them. I just don't think it is a battery or battery cable problem because there is absolutely no indication of power other than the headlights, the brake lights and the dome light. The brightness of these does not change when the key is turned to start. The moment things are ready to work, the radio and dash lights come on in the accessories position and the car starts when the key is turned to start. I think her heavy keychain may have something to do with it. I'll ask the mechanic to turn it off with a little downward pressure on the switch and be prepared to have to lift up and push in on the key to get it started again.

 

There is a fuse that goes directly to ignition switch that is inside the underhood fusebox. It is labeled "IG KEY" and is a 40A. When the car fails next time, have that person see if there is still power on that fuse with a test light or voltmeter. This fuse is upstream of the ignition switch. This will help determine if power is being lost TO or AFTER the switch.