car won't start

[ofdlt10]

driving home monday and eps light came on and lost power steering. got home and turned off ignition. went out later to start the car and....nothing. replaced main relay with my new spare and.....nothing. took dash apart and removed ignition switch. contacts were black. cleaned them and replaced and....nothing. although headlights were bright and head unit worked, no power to the starter. i was told if battery drops below 9.5 volts, windows and starter won't work. replaced battery with a new G35x2 battery and....nothing. removed entire ignition pigtail and looked at the back. see photo.
although most of the solder was still there, enough contact was lost so the above items wouldn't work. new switch arrived today. replaced it and all works as new including eps. although i've never seen this before, i was told this is a common occurrence on hondas and acuras.
anyone else have this occur?

 

[ftuhy]

I haven't seen this on my NSX (I cleaned the contacts before they got too bad), but I've seen it many times in various electrical and electronic circuits. Of the two lower white wires in the picture, one appears all white (or the stripe is not visible), and the other is white w/ black stripe. The solder on the terminal at the end of the white wire is blackened/burned. The most likely cause is the poor connection inside the switch creates resistance, which generates heat when current flows. That's the black you saw inside the switch and cleaned. But the damage to the solder connection was already well on its way. At that point the solder connection is so bad that either a little more heating or a little mechanical vibration will cause the ultimate electrical failure of that connection.

There are a number of classical failures on our NSXs, and based on this forum, the ignition switch is there on the list with the main relay, some years of the O2 sensors, power windows, etc.

 

[link]

Do you have a manual gearbox? Could be the Little tab is broken and not pressing against the clutch safety switch when you press the clutch pedal down. That's what happen to me, ended up bypassing the switch until I get around to replacing the plastic tab

 

[ofdlt10]

no, i have an automatic. the windows wouldn't work, the starter wouldn't engage and when depressing the brake, the safety switch wouldn't release (there was no click at the shifter). the head unit, headlights, antenna, interior lights, open door chime, all worked. also, the eps light came on and i lost power steering. as ftuhy said, if you look at the white wire and the black wire with the stripe, you can clearly see that the solder has completely melted and started to pool at the bottom of the switch near the insulation. after swapping out the switch, vehicle started and eps returned. amazing how much that little switch controls. i'm going to order another new ignition switch and keep it as a spare also.
small price to pay for so many smiles.