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Sc300 Ignition Switch Problems?


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I have a 1995 Lexus SC300 5 speed with only 72,000 miles. Lately, I have had trouble starting the car, and it seems to be getting worse.

The battery is brand-new. It seems as though there might be a problem with the contacts on the ignition switch. If I turn the key to the start position, nothing happens. If I slightly move the key left and right, it finally makes contact at a certain point, usually left of the "start" position, and the engine starts right up. I have a gut feeling that this is an electrical contact problem in the ignition switch. Some members have stated that the starter solenoid can be a problem for some cars with starting problems. But, given the fact that the car starts every time when I play with the key.

Any comments would be most appreciated.

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Just a quick follow-up. Today, I paid special attention to what was going on when I turned the ignition switch. Every time I first turn the key to start the car, I hear the solenoid clicking, but the starter doesn't start turning. After I turn the key back and forth a few times, and more clicking, the starter suddenly kicks in and fires up the engine. I'm starting to wonder if this might be a starter/solenoid problem after all. I had a 1983 Supra that developed a progressively-worse starting problem, some times it started easily and other times I was lucky it started. At the time, the dealer said that the starter had a "flat spot" in the contacts, and therefore wasn't getting current. They replaced the starter and all was fine.

Is there any simple way to test the starter by placing current directly to it to see if it fires up, and thus determine if it is an ignition switch issue, or a starter issue? (Or would it be easier to somehow test the ignition switch?)

Again, any comments will be most appreciated.

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oh ok totaly different situation. if you hear the click and there is no turning action going on then its definitely your starter.

oh if you want to test it (but you really dont need to because its the starter) you can take appart the starter and clean the contacts and slap it all back together and guarantee it will fire up on the first crack. you can just buy the contacts. they are cheap.~10-20 bucks. or you can get it rebuilt for about a 100 bucks.

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  • 1 month later...

Thanks "JZZ30" and "Deton8ed" for all the help. The solenoid contacts ended up being the problem as you both predicted. I bought new starter solenoid contact kits for the battery terminal and the motor terminal from my local Toyota dealer and saved about $20. I bought some car ramps, a 3/8" drive universal-joint socket adapter and a 20" - 3/8" drive extension and was able to repair the starter in about 4 hours 15 min. The starter was a bear to get out of the car from the bottom, but after playing with it about 15 minutes, I was able to squeeze it out the bottom through a very tight space. Once it was out, I opened up the solenoid cover and discovered the worn solenoid contacts. I cleaned the inside, polished the solenoid brass piston surface, and installed the new contact kits. (NOTE: for re-assembly, the factory manual instructs you to hold down the solenoid contacts with a piece of wood using about 200+ pounds of force while tightening the contact nuts. This was WAY too complicated. Instead, I just held down the solenoid piston against the contacts as hard as I could by hand, while tighening down the two contact nuts. For final fine-tuning adjustments, I cut a small piece of paper and held it down between the piston and each end of both solenoid contacts. If the paper slipped out of one end of the contact, I used a wrench to slightly rotate the contact to make sure that the paper was snug. After doing this on both contacts, I was assured that the total contact surface of both contacts was level against the solenoid.

Finally, to make sure that I did not twist the battery-side terminal contact when re-attaching the battery wire, I tightened that nut without the wrench - I just attached a socket to a 12" extension, and tightened the nut by hand (no wrench).

After re-assembly, the starter fired up like new (as predicted by both of you)!!!

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