This how-to will show you how to hook up the oil level sensor light on your 3400 swapped motor. Most 3400 motors already have the sensor on the bottom of the oil pan, we just need a way to hook it up.

Remove the gauge cluster. I traced the leads for the oil light to where is gets its signal from. Turned out to be the top right pin on the back of the cluster. Also you will need to cut out to put in the bulb for the oil light bulb and need to solder together 2 of the traces, which for whatever reason arent connected.

You need to cut out the spot on the back of the cluster for the bulb and insert a bulb. You can see where the traces were soldered together in image 2 below.

On phase 2 clusters, the top left pinout in the cluster bulkhead is for the oil light. I had a spare harness in my basement so I took a wire out of that harness and added it to this one. It is the yellow wire that is added in, in the picture below.

Then I put the cluster back into the dash. Then with the key in the on position I touched the wire to ground and it turned the light on. So far so good.

Next I tested the oil switch and of course it wasn't the way I was hoping for, now Ill have to use a relay to make it work. (The switch is 'on' when there is plenty of oil) This is where the sensor is located in the 3400 oil pan.

Then I added some wire to the sensor pig-tail since the yard cut it off so close. I attached the black wire to ground, and ran the other wire back up to the firewall, close to where the relay comes through.

I havn't taken any pictures of the relay mounted cuz its a bit of a mess & probably be more confusing to look at then to see a diagram.

I had a spare Bosch 87a relay kicking around, so I am going to use it to make this work.

Now just tape (or heat shrink) & solder everything up and your good to go. No more worries about loosing oil without knowing about it.