14.3V out of my EDIC to my oil px switch???

[Cruiser D]

I have searched past threads on the EDIC and didn't find a situation like this. My oil pressure switch was unplugged when I got my BJ70 w 3B. The truck and edic work great both with the switch plugged in and unplugged (yellow/black wire).

While trying to figure out what the dangling yellow/black wire did, I learned it had 14.3V on it while the engine was running. There is also continuity between it and the yellow/lack wire coming out of my edic.

I am confused as to why there is 14.3V present on a 24V system. What strange gremlims could coherse my edic into doing this?

There is only one wire which is tapped off my 12V (low side?) battery, can't trace where it goes, but nothing strange happens when I disconnect it (BTW, it is green with 2 fusible links if anyone knows what this single wire goes). Plus its only 13V.

To make a long question short, why would the edic put 14.3V to the oil px switch, and why does the switch have no effect on the edic's operation?

Cheers
D

 

[cruiser_guy]

When that switch is plugged in I'll bet the truck shuts off next time the Jiffy Lube guys get you to start the truck after an oil change. It happens every time with my BJ60. I get a worried look from the kids working there and then I tell them it's got a low oil pressure switch and I turn it on again and it's fine.
It shuts off because the initial start fills the oil filter before it's able to build pressure. When I change the oil myself I prefill the oil filter so I have pressure right away. I ask the Jiffy Lube guys to do that too bu they don't always do it or they don't fill it all the way.

 

[Cruiser D]

I dunno about that, I changed my oil last week and no ill effects. Tonight I also checked for ground on the switch....no continuity between the frame and the switch's plug both with the engine on or off.

I was under the assumption that when there was no pressure, the switch opened, causing the edic to cut fuel. Thats why the 14V is confusing.

 

[cruiser_guy]

I was under the assumption that when there was no pressure, the switch opened, causing the edic to cut fuel. Thats why the 14V is confusing.

Nope, the switch on my truck is open unless the oil pressure is low. I'm 99 44/100% positive on that as occasionally I find that wire off.
If it was closed on pressure then the truck would shut off if the switch was disconnected.

 

[Cruiser D]

56/100% eh! So you're saying theres a chance i may be right! jk!

So with low/no pressure, the switch will close completing the ground...so if my switch is functional, I should have continuity between its plug and frame.

Have you, or anyone else, ever checked for voltage on that lead?

 

[Greg_B]

There is only one wire which is tapped off my 12V (low side?) battery, can't trace where it goes, but nothing strange happens when I disconnect it (BTW, it is green with 2 fusible links if anyone knows what this single wire goes). Plus its only 13V.D

Evil center tap for your 12V headlights. If you feel inclined to trace it you will discover it runs along the front bib to the right side, along the right inner fender, through the firewall, along the firewall to the left side, ending at the dimmer switch, which happens to be a 12V unit. It's been a while, but I believe if you unplug it with the headlights off, then the headlights will not come on.

The evil center tap is a whole new thread. Do a search for it if you are interested.

hth's

gb