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How to replace the ignition switch
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Reader kevininiowa has submitted this excellent photo sequence of an ignition switch replacement on a '90 Accord, as well as pics comparing a bad switch with a good one.

When working with any electrical item in the car, always remember to disconnect the negative lead from the battery!

Underside of column cover Start by removing the screws that are outlined in yellow. This will begin the removal of the bottom column cover. You may have to play with the column tilt lever, and set the steering column to its lowest position, until you find the "sweet spot" that allows the cover to come off. It will release easier on some cars than others.

On some cars, you may also have to remove the UPPER cover. Again, some gymnastics with the tilt lever and steering column height, along with some careful flexing of the cover itself may be necessary for the cover to come off.

All the foregoing assumes you won't be removing the steering wheel. Things get easier if you do remove the steering wheel, but steering wheel removal presents its own set of problems...

The switch, exposed
The ignition switch is the round thing between the two screws which are circled in green.

Once you remove those two screws, the switch will come right off. The screws go into the back of the lock cylinder.

When you reinstall the screws later, be careful! The lock cylinder housing holes are fragile and easily stripped! Do not overtorque them! A bit loose is better than too tight.

Back of lock cylinder, switch removed
Here the switch has been removed, exposing the back of the lock cylinder (text and circle in red).

The little half-round pin you see in the middle is the part of the lock cylinder that engages the rotating part of the ignition switch. It's what actually turns the switch when you turn the key.

If your lock cylinder is bad, you can remove it and start the car with a small screwdriver. Your screwdriver takes the place of the half-round pin. This, incidentally, is what that crook was trying to do when he forced a screw into your lock and tried to yank the lock out with a slide hammer.

Fuse block connector for switch wire
The last step to releasing the ignition switch is to unplug its connector at the fuse block. You may have to snip some cable ties along the way.

And finally, when you install the new switch, installation is the reverse of removal. And don't forget to put the rubber ring back around the keyhole! You wouldn't want to get the whole thing back together and then realize you forgot it, would you?

Now...what was wrong with this puppy? kevininiowa tells us...

The contacts, close up
This is the NON-rotating part of the switch (the rotating part appears later). The contact functions have been marked on the photo. This is the side that faces the ignition key.

In yellow is the pitted spot that caused all the trouble. It's part of the IG1 circuit, so it's what provides power to the Main Relay, and is "hot" all the time while the ignition is on. IG2 is the smaller one next to it.

So long as you hold the key to START, contact is made at the un-pitted end of that contact. As soon as you release the key to its normal RUN position, the pitted end has to carry the current. Poor connectivity results in high resistance and overheating.

If you look closely, you'll see the shiny path on each contact, worn by the ROTATING part of the switch, the contact piece.


Back of switch - melted solder
Here's the back of the switch. Notice the melted solder, circled in red. This was caused by overheating due to high resistance on the other side, where the pitting was.

Circled in grey are the connections that were still good.

Other contact side of the switch
And here's what made those shiny paths two pictures ago. It's the contact piece, inside the switch cover. This is the ROTATING part you turn when you twist the ignition key. The bumps slide and make contact with the silver contacts on the non-rotating part. The small one right at the top is what touches the START contact in the pic above.

WARNING:
When removing the cover and taking out the contact piece, there is a spring in there that needs to go back in correctly, or the switch won't move back from the START position to the RUN position.

Old and new backs, compared
Old and new switches, compared.

In this photo, both switches have their covers still installed. The contact piece is retained by the cover.

Contacts, new and old
Old and new switches, compared again. (New on left).

The covers have been removed, along with the contact piece. If you look closely at the high-res picture, you can even see the grease on the new switch.

Kevininiowa was able to restore the old switch to temporary functionality by simply re-soldering the pitting and the connection on the back. This way he could at least drive the car until he got around to replacing the switch.


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