Since about two oil changes ago, I have been having some erratic oil pressure guage operation. While looking into the problem, I noticed that the there is a sensor mounted low in the block, just below the starter with a wire broken off (there is photo of the sensor on page 174 of the haynes manual). Is this the oil pressure switch? If this is the oil pressure switch, can this cause erratic guage readings? It seems to run just fine, and occasionally the guage will read correctly, but most of the time it reads low. I would think that it was the engine, but it started all at once, like something that could have been triggered by a broken wire. I did a search and found a couple of posts that mentioned the oil switch, no definitive answers about the switch affecting the gauge. I know the gauge is driven by the sender, but can the switch with a broken wire cause poor gauge readings? It seems odd that the Trooper even runs with a wire broken on the oil pressure switch <img src="/forums/images/graemlins/confused.gif" alt="" />

The sensor below the starter is a oil warning switch, the oil pressure sending unit is mounted right above the oil filter, and they tend to act funny before they go out. I have one if you want it, think I gave $10 for it (cost over $30 new), send me $10 and I'll ship it to ya. PM me if you'd like....
BTW, the switch with the broken wire you speak of is $11.99 at AutoZone, I just replaced mine. Thought that would help <img src="/forums/images/graemlins/rolleyes.gif" alt="" />
Later,
Nick

There is a pic of it on page 106 of the Haynes.

Nick,
$10 consider it sold! I will probably hook up a mechanical gauge for a bit, just for a sanity check. Don't you want some shipping thrown in there too. I'll send you $20 to make sure that shipping is covered. PM me with your address and I will put a money order in the mail on Monday. I replaced the switch, I really don't think it will have any affect on the gauge, but it was only $12. So it can't hurt to replace it. And while I had the tire off, I noticed that I had a brake pad that was totally shot. I should have seen it the other night when I was messing with my auto hubs, but I was so focused on the hub I did not notice that I had a pad that was almost completely shot.
Thanks,
Kris

Sent ya a PM.... <img src="/forums/images/graemlins/kewl.gif" alt="" />
-Nick