Rebuild your ignition switch: Intermediate, Trailblazer 9490

[BlazingTrails]

You may be asking yourself, why would I want to rebuild my ignition switch? Well after you see how simple it could be you may decide to give it a try. The design is overly simple, and unless your switch has melted very easy to refresh. This procedure will save you money, and if you are broken down this procedure may get you on the road quickly.

I am going to take this further and suggest to you that you need to change/refresh your switch whether you know it or not. If you are experiencing any of the following, start with the ignition switch!

♦ Misfires
♦ Rough idle
♦ Poor Fuel Mileage
♦ Power loss
♦ Transmission not shifting
♦ Instrument cluster not working
♦ Lights dimming
♦ Any of the following codes P0740, P0753, P0758, P0785, P1860, P1633, and more
♦ Random CEL codes, that come back over and over again
♦ Many other symptoms not listed

Supplies needed:

♦ Contact cleaner
♦ Emery cloth minimum of 320 but 600 grit would be best.
♦ Heat gun/hair drier
♦ Dielectric greas
♦ Basic hand tools

Let's begin shall we?

After removing the "dust caps" (side covers) from the switch remove this screw. This will disassemble the entire switch.



It will look like this









At this point it will be necessary to remove all of the old grease from the switch, and thoroughly clean the moving parts, pins, and case.

Next you are going to clean the contacts, they are made out of copper and easily get corroded.



It is CRITICAL that use use a fine sandpaper, I chose a 1000 grit sand paper, However as you can see in some of the picture the best material to use is emery cloth strips.







You will need to pull the emery cloth back and forth many times, you need to think of this as polishing not sanding. You want a very smooth surface because you need maximum contact surface.

Once you have cleaned the contacts and verified they are shiny, spray them with some contact cleaner and dry thoroughly with a heat gun or blow drier.



Now comes the dielectric grease. This will keep the contacts from getting corroded in the future.



Also apply the grease where the pins and moving parts will make contact with the case.





Reassemble the switch, don't worry the gear will only go in one way.....don't force anything.



Snap the dust covers back on. Then ad some dielectric grease to the main power pins.



DONE! The devil is in the details, this is a simple procedure but you must be thorough for it to be beneficial!


If you have any question about this procedure feel free to send me a private message.







9490 <--- For searching purposes

 

[DAlastDON]

Nice wright up. I had planned to do this a couple times now but something comes up and i postpone it. Hoping it will clear up the intermittent service 4x4 gremlin at startup. Nothing wrong with the wiring, grounds, or mechanics that i can find. Only thing left is the power supply through the ignition switch. A loss of a few tenths of a of a volt on the reference voltage could be the cause of the failed self test at startup.

 

[kickass audio]

Great write up!! I replaced the ignition switch on my mom's 02 Impala and opened up her OEM one and the contact pins were all full of carbon so it's no wonder why it had random problems. She still has issues with the security system on the car because of the remote start and I can't figure it out but whatever, it works and we don't care. lol.

Only thing I can think to add is when someone goes to replace their ignition switch would be to first tape the part where you would insert the key to hold it in place so it doesn't move around while you replace or repair the switch. I would also take a sharpie and mark the gear and body of the ignition switch so you know what way it needs to be aligned up when you reinstall it. You don't necessarily need to do that but when I replaced the ignition switch on my co-workers Envoy, the alignment was off by one tooth and we played with the alignment on it a few times for like 20 minutes to get it to work as normal.

 

[BlazingTrails]

Great write up!! I replaced the ignition switch on my mom's 02 Impala and opened up her OEM one and the contact pins were all full of carbon so it's no wonder why it had random problems. She still has issues with the security system on the car because of the remote start and I can't figure it out but whatever, it works and we don't care. lol.

Only thing I can think to add is when someone goes to replace their ignition switch would be to first tape the part where you would insert the key to hold it in place so it doesn't move around while you replace or repair the switch. I would also take a sharpie and mark the gear and body of the ignition switch so you know what way it needs to be aligned up when you reinstall it. You don't necessarily need to do that but when I replaced the ignition switch on my co-workers Envoy, the alignment was off by one tooth and we played with the alignment on it a few times for like 20 minutes to get it to work as normal.

I am working on a detailed ignition switch install and circuit test thread. Should be posted this weekend.

 

[Mounce]

One thing I'd add is that the most common precursor/proof of a bad (corroded) ignition switch is as follows:

*ABS light and BRAKE light on cluster comes on randomly then randomly goes away

* HVAC blower goes out as well at the same time but comes back when lights go off


I took one of the old ones apart after I replaced it and could see that some of the contacts had got hot and discolored the the copper, alluding that they were dirty. Didn't realize how simple they were to clean though, nice info and I'll try it next time mine goes out.

 

[Mounce]

Just thought I'd add this for some proof of self-corroding contacts.

Happened to see the old ignition switch today so decided to take a look at it and check out the contacts.

Here's the discolored "prong" I mentioned in my last post, you can also see where my fingerprints corroded the prongs over a few months time:

And here's pics showing the corroded contacts:

 

[Mooseman]

Another thing that could be used for the lower unmovable contacts is a burnishing brush. It's glass fibers on the tip and would be able to reach the recessed contacts.