Ignition Switch- Using dielectric grease

Hello, I am a bit confused as to how to use dielectric grease in general, really.

1. Car sometimes does not start: turning the key does not crank or dim the lights, you just hear a click.

2. I figured it was the ignition switch, so I pulled it out and gave it a clean according to wiki.

Easily found the part after taking the cover under the steering column off. The hard part was inverting myself underneath there. This also gave me a headache so I wouldn't mind paying someone to do it next time:


Me taking a selfie under the car. Being cramped and sweaty and upside down was not fun, but it was a great learning experience.


The switch after prying the mating barbs open. Was quite difficult but you really don't have to be that delicate:



After cleaning with alcohol:


Placed dielectric grease on the contacts for both parts (I think this was wrong):


3. Put it back together, ran it. The car would turn but would die immediately after. If I held the key while turning, it would stay on. I even got it to stay on if I put some gas into it. I figured the grease was a stupid idea.

4. Did it all over again (on a different day) but cleaned the contacts with alcohol and reinstalled it. Worked fine.

Was I not supposed to use grease in that manner? Next time this starts causing problems I may just replace it. Cleaning it was fine but let's see how long the cleaning lasts.


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Dielectric grease is an insulator. It is used to keep moisture out of things. Most contacts should have sufficient pressure to wipe through the grease and make contact but that appears not to be the case with your switch. Most people seem to replace them with a new one because the part is not all that expensive as I remember it.

Yes that's what happened here I think. I guess the spring pressure isn't strong enough to push the grease out of the way?

I am thinking of using some for my battery terminals.

As jwmelvin notes, dielectric grease is an insulator. It is typically a silicon base and common automotive use is to apply it on the coil (coil on plug) or sparkplug boot where it slides over the sparkplug. It helps to seal out moisture and makes it easier to pull the boot / coil off the plug when its time to change the plugs.

The grease that you should have used is something like Ox-gard. It is a relatively high temperature grease with incredibly fine pieces of metal embedded in the grease. Apply the grease to the switch contacts. The grease prevents / slows down oxidation of the metal contacts (which the pure dielectric grease will also do); but, when the embedded metal particles are trapped between the pressure of the two switch contacts, it improves conductivity across the switch contacts.

There are different types of this conductivity improving grease, supposedly geared to matching the type of metal in the wire or switch contacts. Perhaps if you are doing up the connectors on a 500,000 volt transmission line, that kind of chemistry match is important. I find that for use on the car, the plain-jane Ox-gard that Home Depot sells works just fine. Ox-gard is good to use on connectors that may have environmental exposure or any place where you experience a compromised electrical connection.

Don't feel bad about using the dielectric grease. I think that is a really common mistake.

You can use the dielectric grease on your battery post; but, it is a little expensive for that. Just about any old grease will do a good job of sealing the posts and connectors from moisture. Save the dielectric grease to grease the boots on the nose of your coils when you do your next sparkplug change.