I’m looking to wire in a digital voltmeter, oil pressure guage, and water temp gauge in my 1987 f150 xl 302 5.0, i don’t rlly know if any of the wiring has been messed with but primarily how would I even go about this step by step, I’m new to wiring and just working on trucks in general, and have never wired anything into anything before, I’m assuming I need a wiring diagram but what one do I need to look at, and what do the gauges all need?

 

First step whenever working with the electrical system is to disconnect the negative cable off the battery.

I can tell with my experiences with my 87, the dash gauges are erratic, they stick and are junk.

I added my own electrical oil pressure gauge years ago.. The requirements are basically the same for any gauge.I ran new wiring instead of trying to figure the original wiring.

I tapped into the "protected" side of the radio fuse for gauge power, gauge ground attaches to the chassis. The gauge comes with a new sender which replaces the oil pressure switch screwed into the engine block. I just taped up the old wiring aside .I ran a #18 wire from the "sensor" connection on the gauge to the new sending unit. That basically would apply to a temperature gauge except you are wiring to the "single wire" temperature sender on the block.The wiring to your new DVM can be attached to the battery clamp bolts by adding a nut for attachment.

If you can solder, you will be ahead if you can solder all lugs to new wiring instead if crimping alone.If you can't solder, crimping will do.

Good luck with your project.

 

Yes, do what raski said
Mount the gauges first so you can deal professionally with the wiring
Deal with one or two wires at a time, and make it look as clean as possible using convolute tubing (sheath), good UL listed electrical tape and black wire ties
Add wires like raski said, and leave your trucks gauges and wiring alone
Add senders using tees if needed

 

I also have a 3 gauge set, but is there a way to make it so both original and aftermarket gauges still function?

 

If your factory gauges were operational, tapping into their feeds would give signal to both of them.

 

This would work if they were completely electronic, but the oil pressure has a tube running to the engine and the coolant temp also has something similar.

 

Remove the oil sending unit from the block, put a 3” extension tube and a brass Tee, one end goes on extension tube, one end the mechanical oil port and other would be the factory sending unit.

Coolant temp, you can buy a Tee and place it on the heater hose that comes off the water pump close to the pump to reduce heat loss in the hose.

 

Not true. They each have a single wire to the sender, not a tube.If so, somebody made it that way.

 

I don't know why you want both? The dash gauges are unreliable. I see no reason why someone would want both. You would have to add tee's so that each sender can be screwed into an individual port on the tee.

 

I took his statement that the three gauge had a mechanical oil pressure.