Symptom: When turning the key to 'start', 70% of the time the car will start up just fine. Sprinkled throughout that 70%, all other times I'll turn the key and nothing will happen, exept for a "Hummmmmmm" (power brake booster, or other system responding). Continued attempts it will start up as if it were brand spankin' new. Oddness!

Troubleshooting: Removed battery connections, wire brushed and cleaned up & tightened. No change. Replaced starter relay, some improvement for 2 weeks, but now the same intermittent problems returned.

Today I noticed a clue: That purty green light that surrounds the ignition keyhole doesn't stay on full-time....is it supposed to? Seems like I remember that being illuminated full-time. Perhaps there's a prob in the ignition switch mechanism/connections. Any thoughts? (before I have to remove the steering wheel to investigate ) I'm mostly asking about that green circular light. Can anyone please verify when it should be illuminated? (aux, on, start, etc?) It seems to respond to jiggling the key in the ign. I couldn't find anything in the Haynes or owners' manual, and my FSM CD is packed away somewhere. Thanks!
-Alan

 

As recall the green light went out after a time once the engine was shut off.

You don't need to remove the steering wheel to access the ign system (suggest you don't!) but the upper and lower covers.

Doubt the issue is connected to the green light, as it is not wired into the ign system for starting the engine but the cars lighting system.

If you think jiggling the key helps use a short section of electrical wire to jump the small electrical terminal connection on the starter solenoid to the battery cable connection of the solenoid. This connection will bypass the ign key system.

Jump only the small terminal to the larger battery cable connection (not the two larger terminals) This terminal receives 12V DC power from the ign switch circuit when the key is turned to start.

If the above works it could be the ign switch, its wiring or the starter relay.

Note: This starter relay is not the starter solenoid but a much smaller relay that goes between the ign switch and the connection to the starter solenoid.

If this test does not work proceed with the following:

Check connections between the battery cable terminals and cables.
Check the ground cable connection where it connects to the chassis.
Check battery cable going from battery to starter solenoid for high ohm resistance.

Obtain battery cables.

When the engine refuses to turn over use a jumper cable to connect between the positive battery terminal and touch the other end to the terminal of the starter relay that goes to the starter motor. If the engine turns over the starter motor, ground cable and electrical strap between the engine and chassis is OK. If not check these items.

If the starter motor works as tested above, now connect the jumper cable to the starter solenoid terminal the battery cable connects to and try to start engine. If it starts check the battery cable between the starter solenoid and battery.

If not use the small section of wire to jump between the positive battery connection terminal of the starter solenoid and very small terminal on the solenoid. This small terminal receives 12V power from the ign system to energize the starter solenoid.

If the starter works the problem is the starter relay or ign switch circuit or starter relay.

If not check the negative battery cables and electrical ground strap between engine and chassis.

You can do this by connecting the other battery cable directly from the negative battery terminal to a metal part of the starter motor.

When doing tests leave the cars battery terminals connected to the battery.

 

Wow, thanks Joey for the specific troubleshooting info!! I will try these in the coming days and report the findings. Hard part is finding exactly where these pieces/parts are located to test. But where there's a will, there's a way, and where there's camryforums, there's a means.
-Alan