7 replies to this topic

[turbogolf]

Hi guys, I just recently cleaned the PNP on my '93 850. The car was having problems shifting during the winter and the back-up lights would not turn on when in reverse. I followed the instructions here on Volvospeed and took out the PNP. But instead of replacing it with a new one, I thought I would take it apart first and see what's going on. The copper contacts were in great condition, but the grease that was originally filled (over 13 years old now) had formed a hard layer so thick that the copper contacts were unable to form a connection with the leads. So I took out the three copper contacts that were on the "moving head" and clean out all the old grease and replaced it with something new. The contacts were then sanded a little to ensure a positive connection. After that, I put everything back together and hoped for the best. To my suprise, everything is working perfectly now. The car is shifting when it suppose to and the back-up lights are working as well.

I thought I would post this as a cheap way to fix the PNP if you have a little extra time. It could just save you $100 bucks!

[MadeInJapan]

That's great! Did you take pictures? This should be a sticky in the above section.

[turbogolf]

That's great! Did you take pictures? This should be a sticky in the above section.

I should have taken some pictures
I didn't think this was going to work. It wasn't until I started the car and check out the lights until I realized that it did actually fix the problem. One problem I did encounter was the 6 screws holding the PNP switch together were all rusted onto the cover. I tryed WD-40 and etc but nothing worked. Finally I drilled out the old screws and bought some new ones from HomeDepot. I think the screw size is M4-7 or was that M3-7, I forget. All in all, the total cost of the repair was the $0.79 spent on the screws.

[lcc014]

I should have taken some pictures
I didn't think this was going to work. It wasn't until I started the car and check out the lights until I realized that it did actually fix the problem. One problem I did encounter was the 6 screws holding the PNP switch together were all rusted onto the cover. I tryed WD-40 and etc but nothing worked. Finally I drilled out the old screws and bought some new ones from HomeDepot. I think the screw size is M4-7 or was that M3-7, I forget. All in all, the total cost of the repair was the $0.79 spent on the screws.

What kind of grease did you used to re-pack the PNP switch ?

Thanks,

Ching-Ho Cheng

[PullMyFinger]

I'm guessing dielectric grease. As in any moving electrical connection. Can also be used on spark plug caps.

[lcc014]

I'm guessing dielectric grease. As in any moving electrical connection. Can also be used on spark plug caps.

Thanks for the suggestion.

Ching-Ho Cheng

[turbogolf]

What kind of grease did you used to re-pack the PNP switch ?

Thanks,

Ching-Ho Cheng

Yup, I used some dielectric grease. Coated all internal surfaces and made sure the spring loaded copper contact pieces were free to move (they had previously been held in place by the hardening of the old grease). I also used a multimeter to make sure that the contacts within the PNP switch were connected to the output pins on the plug before I did the cleaning, because if the wires were loose or cut, no matter how much you clean the inside, the PNP still won't work. Hope that helps!

[lcc014]

Yup, I used some dielectric grease. Coated all internal surfaces and made sure the spring loaded copper contact pieces were free to move (they had previously been held in place by the hardening of the old grease). I also used a multimeter to make sure that the contacts within the PNP switch were connected to the output pins on the plug before I did the cleaning, because if the wires were loose or cut, no matter how much you clean the inside, the PNP still won't work. Hope that helps!

Thanks for the useful information.

Ching-Ho Cheng