I am in the middle of finishing my gauge cluster swap. I have the new cluster in and working and am changing out my sending units from the dummy light versions.

I have the new oil pressure sending unit in, but the oil pressure gauge is pegged out as soon as I turn the car on. I don't know if there is a problem with the ground, or the cluster. Can someone tell me if the gauge version of the oil pressure sending unit has a single wire that goes into it or a pair?

Also, I am attempting to remove my temperature sending unit, but the valve cover prevents me from getting a socket in over it, and it seems near impossible to get a wrench around it, does anyone have any suggestions?

Thanks

 

Pull your V, cover and clean it real good, pull the sending unit then, and change your oil. Then test your Oil pressure to see if it is you gauge or something else.

 

Did you buy the correct sending unit? Both only have one wire/connection. Wiring for a light WILL WORK for full gauges if you have the right sending unit. I'd check the part number to ensure you have the correct sending unit.

For the temp sending unit, I was able to pull it with a pair of channel locks. Spray it with penetrating oil to make it easier and then slowly work the unit out. Sure it only moves a fraction of a turn at a time, but it really doesn't take that long to get it out and it is way easier than pulling the valve cover. Plus...when I pulled mine, coolant started flowing out of the hole. Do you want that underneath your valve cover?

Good Luck,
s

 

I didnt have any trouble at all getting my temp sending unit out if i remember right i used a 13mm gear wrench and it got on to it just fine.

 

The sending unit is the one for the gauge version. Question though, is there a difference between an oil pressure switch and an oil pressure sending unit in a Cherokee? The gauge is pegged out whether I have the sending unit connected or disconnected which leads me to believe that its the cluster or the wiring itself that I am having a problem with. I am going to pull out the cluster and clean the connections as soon as I can, and make sure I don't have any visible grounding problems. Can anyone confirm for me that when you disconnect the wiring from the sending unit that the gauge should read 0 with the ignition in the on position?

As for the Water temp sender, someone advised for me to use a crows foot wrench, would this be advisable if I am unable to get a 13mm socket fit well enough onto it to crank it off?

Thanks

 

Yes there is a difference bewteeen a switch and a sending unit, but the sending unit will look similar to the one you pulled so there shouldn't be any confusion. Any time I've read about gauges pegged out I have heard the remedy was a new sending unit. I would try to replace the one you bought to see if it was defective (as long as you are sure it is for the gauge and not the light cluster. Regarding the possible cause for the reading, I would think that a grounded wire or otherwise faulty connection would have resulted in a light illuminating prior to the gauge swap unless you caused these issues when you were working on it for the swap. For the sake of clarity, the oil pressure gauge gets pegged out when the vehicle is running or when keyed on?

Really, I think any tool you can get to work would be just fine. Take a set of pliers, channel-locks, socket, crow's foot, rib spreaders, and anything else you have available and stand on a stool beside your driver's side fender. Surely you should be able to get something to work. I didn't find it particularly difficult on my 96 or on an 88.

s

 

The gauge stays nearly pegged out when their is no key in the ignition, moves to pegged out when the car is turned on, and stays pegged out once it is started.

The box I have is labeled "oil pressure switch for gauge version."
But the "switch" itself looks just like a longer version of the oil pressure sending unit that I replaced. It fits the same exact plug, but instead of having a single output lead on it, it is a 2 wire lead which is what lead me to believe the wiring may have been different between the two.

What throws me off is that the gauge reacts the exact same way whether the wire is plugged into the sensor or not.

 

I'm pretty darn sure that the sending unit that I have only has one connection to plug in (90% sure). What year XJ do you have? Also, when I was doing my swap, I noticed that there were different sending units for the Canadian model. Try looking it up on rockauto.com It will be under electrical switches.

Oh and after a bit of research I think there is just the one oil sending unit so there shouldn't be any confusion between a switch and sending unit (they aught ot be synonyms). The temp switch and sending units, however, are completely different. Let me know what you find out. What brand switch did you get and was it the part number?

s

 

So you are saying that the unit should only have a single visible pin in it? If so I will go back to the shop and check it out with them today. Its a 96 XJ.

 

That is what I have and I just did the gauge swap myself. I remember looking at the new sending unit and thinking that it was odd that it only needed one wire like my idiot light version. That is why I'm 90% positive it only has the one connection. Definitely go to shop to see what you can figure out. You might want to also check you vin to see if it is a US or Canadian model. Check it here: http://jeep.avtograd.ru/VIN/vin_en.asp

I know this doesn't help with the specific question, but you may want to read over this to see if you fudged any steps. http://jeepin.com/features/gaugeswap/

If this doesn't work out, I'll pull my connector tomorrow to see how many connectors it has out back for confirmation.

 

Alright, went back to the shop, sure enough it was the sending unit. For some reason they had a different gauge version of the oil press sending unit listed between the 95 and 96 cherokee. Switched out what I had for the one for the 95 which did only have one pin and it works like a charm.

Thanks for the tips guys.

Now if I could only find an easy way to get the water temp sender out, I think I will pickup a crows foot set tomorrow and make my life a little easier.

 

Sounds like you've got it sorted - but I've found that, when you're using self-grounding sensors (like the oil pressure sensor, or the coolant temperature sensor,) that using PTFE-based compounds can cause the sensor to be insulated from the mounting - meaning it's going to be "maxed out."

Solution? My "never-fails" has been to use RTV Copper on the threads instead - since it actually is a copper-bearing silicone, it will both seal and enhance the electrical connection. I don't use anything else on self-grounding sensors.

That was what I was going to suggest after checking the sensor with an ohmmeter - but it sounds like you've got the current problem sorted.

 

Awesome. I'm glad you got the sending unit to work . Was I right that the sending unit only had the one connection? With the temp unit removal, I hope the crow's foot strategy works. Like I said before, when I removed and installed two units on different XJs, all I needed was a pair of channel locks. The sending units were swapped out in just a few minutes.

s

 

I love it when simple changes take way more effort then they should.

I picked up a crows foot wrench to make removing the water temp sender a little easier. Turns out with the angle the bolt is at, and being pressed up against the valve cover so closely I still couldn't get a great angle on it. Socket will not fit over the top, and I'm running short on ideas to get it out short of removing the valve cover. At this point the unit is stripped on one side.

At this point should I pull the valve cover, or does anyone have another idea on a good tool/way to remove it without taking off the valve cover first?

 

I think I just used a six-point socket last time I changed it. Either that, or a flare nut wrench.

Either of those should neatly clear the valve cover, and using a six-point socket will afford you a better grip on the brass body of the sensor (using a 12-point socket is not recommended there - too easy to round the bugger off!)