MJ cluster swap, few questions.

I have an '90 MJ auto with the stupid dummy lights. I just obtained a cluster with the real gauges. So, am I correct to assume I need a new oil pressure and temp sending units? Also, regarding the tach. I have read in some places the tach wiring is already there, so just installing the cluster will work fine. Others have said you need to run a lead to the new cluster. Not sure if this is only for certain years or if it is just a mixup in information.

So, just wanting to clarify before getting into it. Thanks

Hey Jeremy! :wave: I haven't done the swap myself, but I've always known it as a plug-in-n-play procedure after installing the temp and oil sending units. This is the first I've heard about running a new wire for the tach. I ran a lead for my aftermarket tach, but that was simply because the directions said to.
Jeep on!
--Pete

Ahh, hey Pete

And that is what I thought as well, so I should be good to go. Although I do have the pansy column shift auto with the little gear gauge in the cluster.. but screw that. The little indicator is off by one full gear anyway, so I won't try getting that to work in the new one

The wire for the tach should already be in the harness. Just plug it in and see. Don't worry about getting a cluster from a 4 vs 6. As it turns out, the pulse sent from the system is based on revolutions and not cylinders like ignitions with points. In other words they both work the same. If you are running a 2.5L or 4.0L, there are two temp sensors. You want the one on the drivers side at the rear of the head. It takes a 1/2" or 13mm deep socket to replace.

As a note: Pulling this sensor can burp any air pockets in your engine when you just fill up the antifreeze.

Tom Houston
Loveland, Colorado