Hi everyone,

I'm looking to add an aftermarket tach to my '85 Bullnose (it is a tach-delete model, that also has no factory radio)... and I'd like to do a permanent, clean installation (no hanging wires, no wires "jumped" into other fuses etc....).

My questions are:

1) How can I wire the red and white wires into the fuse box?
2) What sizes fuses do I need for each (10 or 15 amp or more)?
2) Are there any kits that can provide any needed crimping tools, extra wire and also suitable fuses?
3) Can I run them into available locations in the fusebox from the back of the fusebox?
4) Where can I run the ground?
5) I'll need a small grommet to feed the wires from the back of the tach into wherever I mount the dash. Does anyone have any sellers/recommendations for rubber grommets?

Thanks.

 

Fuse taps are really the only way you are going to get power from the fuse box. If you do not like that idea, then you can run over to the radio and tie into it's ignition on power wire. You would only need a 5 amp fuse to run the tach.

The ground can be picked up anywhere there is a bolt nearby going into a piece of metal to the body. The whole bottom of the dash is metal.

The Help! section in the parts store usually has a grommet assortment you can buy. You can also cut a short piece of vacuum line and run your wires through it, and run the vacuum line all the way up to the bottom of the tach, so you have one clean black piece leaving the tach and going through the dash. You can also use a piece of vacuum line when you go through the firewall to protect the tach signal wire. Or most of the time you can poke a hole in a piece of rubber around the steering column area and run the wire through that.

 

Thanks Franklin.

Unfortunately, the truck does not have a radio or speakers. The space in the dash just has a factory supplied, plastic plate over it.

So, I guess I'll have to run them right into the fuse box and tap into some of the existing fuses.

Speaking of that, how do I connect the wire? Do I just wrap it around one of the pegs of the fuses?

Also, just to confirm - I can connect the ground wire to just about any bolt that is bolted to the bottom of the dash?

Thank you for the tip with the vacuum line. I actually need to buy some as the A/C air controller module isn't working - all air gets diverted to the windshield vents regardless of the selector setting, so there has to be a vacuum leak somewhere...

 

If you thought you had to wrap the wire around the fuse, I can see now why you did not want to do it. Go to the store and buy one of these. Then get a slip on spade connector/crimp and connect the wire to the crimp and just slide it on the fuse tap. The piece below is Advance Auto part number 85606. That also happens to be the Dorman part number, you can buy it on Amazon and lots of other parts stores.

 

Are you planning on putting the new tach in the instrument cluster in place of the current blanking plate?
https://www.ford-trucks.com/forums/9...4-f-150-a.html

Jim

 

Thank you for the information, Franklin.

JimsRebel - thank you for the link. I'm actually going to mount it on the steering column or the top of the dash.

 

Jim do you have the picture from your post in the link above about "The connector is on the left inner fender well near the Duraspark 2 module shown in the photo."
I would like to make sure mine is plugged in the next time I am in the garage as I don't remember the tach working.
Dave ----

 

On an 80-83 it is tied in with the DS2 IGN module, meaning the 4 wire plug has an extra green wire so 5 wires total. On a V8 engine there are 6 wires total as there is an extra green and black wire. The black wire adds an extra ground for the tach to handle the 6 or 8 cylinder calibration.
Here is a photo of the tach dicconnect plug of my 86 six cylinder engine. It is the top plug in the photo, it has 1 green wire on the engine side and 2 wires (black and green) on the firewall side.

 

Here are some more photos, the first photo is a V8 harness, it has 2 wires on the tach feed plug (rt side of pix)

 

Thanks for the information, now I know what I need to look for.
I am sure it will help others.
Dave ----

 

I've used this style tap in the past, but one thing I don't like is they tend to spread out the fuse box contacts. The only time this would be an issue is if you ever remove the tap, so this isn't really a big deal, but is something to consider.

I've seen this other style, which plugs in place of the original fuse:





I haven't used one yet, but if I ever need to tap into a fused circuit, I plan to try one of these. I especially like how it adds a second fuse for the new circuit, so you're not overloading the fuse for the original circuit.

 

That looks like a good idea. I have had the fuse box contacts spread sometimes on mine also. Like you said, you are better off leaving the fuse tap in place. Reminds me of that genie cheat cartridge my daughter plugged into her Nintendo years ago, and it ruined the socket in the game console.