Dielectric Grease on Fuses and Relays

[ZZman]

I am on another car forum and one member said pulled his fuses and found them oxidized and tarnished so he pulled them all and cleaned them up with sandpaper and then used dielectric grease on them. He said the car seeme to start faster and lights etc.... appeared brighter.

I did an oil change today and pulled all my fuses and relays and cleaned then up and used dielectric grease on them. They were tarnished.

I thought this was a great idea. We will see how it works.

 

[StevieC]

I have always put a good quality penetrating fluid or a bit of engine oil / dielectric grease on "serviced" electrical connections and never had a problem. Adding anything to the connection may increase the resistance a bit though... Nothing to worry about in most cases and a good trade off for reliability IMO.

 

[JTK]

I don't know that I'd want anything hydrocarbon based in/on there. Silicone based, sure.

Joel

 

[mechtech2]

I wonder what fuse he cleaned that are in the starter motor circuit?
Normally the cable is right from the starter to the battery.

 

[demarpaint]

I always thought it was a good idea but wondered if putting it on sensors like the ECT, IAC, TPS, connectors could effect the readings the computer is getting from them?

 

[brianl703]

Ford used to use a lithium-based grease on sensor and computer connectors.

Now they use a grease like Nyogel 760G.

 

[jcwit]

Got a used Kia Rio, and did this shortly after I bought it (3 yrs ago). They were the small relays that have a plastic cap, made by Denso, no better way to explain it, anyway ended up replacing 5 of the relays within a month after appling the dielectric grease, tried to clean them off with spray contact cleaner to no avail, like I said had to replace them. Was not some other issue because they did not go bad all at once, and replacing them has worked for 2 yrs now.

Got real interesting one time 150 miles from home, at grandma's at 10:00 at night and no lights. That was my first experience with the dielectric greased relays, so replaced the light relay, then later the A/C relay went, then the horn, ect, ect. Nothing more now for over 2 years. Just my experience.

 

[George7941]

One of the first things I did when I bought my Sierra was to apply dielectric grease to the terminals of the relay panel. One by one the relays started malfunctioning. One day I would not have the horn, next day no high beams. The Delco relays have a removable cover (can) on them and I noticed the grease had migrated to the inside of the can and on to the contacts. Wiping the grease off the contacts would restore the functioniong of the relays for another month and then they would need another cleaning. Problems persisted even after removing as much of the grease as I could from the relay panel. I replaced the Delco relays with these potted relays
http://www.delcity.net/store/With-Resistor-!-Miniature/p_791799.a_1
I have not had any more relay problems.

At one time, when quick-disconnects (1/4in flat)were widely used and the connectors were not weatherproof, grease helped retard corrosion. Current weatherpack and metripack connectors are so well sealed that I never see corrosion on them, even with no grease applied.

Stabilant 22 is highly regarded by some professional mechanics and is even marketed by Standard Motor Products. It is what I now use on terminals.
http://www.stabilant.com.au/what_is_stabilant_22_.html

 

[ZZman]

Originally Posted By: mechtech2
I wonder what fuse he cleaned that are in the starter motor circuit?
Normally the cable is right from the starter to the battery.


There is a large 40 amp and a small 30 amp related to the starting system.

 

[Vizzy]

For simple connectors (eg tail lamp pins, ect) especially if the item is possibly subject to condensation turn signal housing connectors...BUT I WOULD HIGHLY RECOMMEND AGAINST APPLYING SUCH STUFF TO COMPLEX INTERIOR ELECTRICS!!!!!! Just as a previous poster mentioned applying ANYTHING may negatively affect voltage to items that are very small draw and this could SERIOUSLY affect functioning!!!!!

IF IN DOUBT LEAVE IT ALONE!!!!

 

[doitmyself]

It seems counter intuitive to put a non conducting grease on an electrical connection. But, I suppose that the contact force of the connector pushes enough of the grease away so that there is metal to metal contact for current to pass.

 

[Vizzy]

Originally Posted By: doitmyself
It seems counter intuitive to put a non conducting grease on an electrical connection. But, I suppose that the contact force of the connector pushes enough of the grease away so that there is metal to metal contact for current to pass.


This is true for most simple uncomplicated connector issues, BUT definitely not true of complex or very low voltage applications..that may use multiplexing electrics.

 

[mechtech2]

ZZman - 30 and 40 amp fuses can't carry starting current, so they will have no effect on cranking.
I don't know how or why there are 2 mid amp fuses in a 'related' starter system. Maybe the solenoid wire?

 

[KrisZ]

The fuse box on my car it sealed from the elements, I checked it once already and everything looks good, the seal in good condition and no moisture and dust inside the box. So I don't see the need for any type of grease.

On my headlight harness, however, I did apply some silicone grease, as the harness is exposed and already showed some residue on the contacts.

 

[PT1]

Dielectric greasing the fuse panel is SOP on my Harley. Lots of reports of bikes not starting and when the fuse panel is cleaned and greased they start right up. Not necessary in the car as the fuse boxes are closed pretty tight.