Electrical questions

[j69302]

Im trying to figure out how to get switched power to 3 Autometer gauges that I just bought. I know there are companies that make auxiliary fuse blocks to tap power but they seem to use a relay triggered by the ignition switch to draw power straight from the battery which requires more wiring than is necessary for what I need.

So I was poking around my fuse block with a 12v light tester and found a unused slot which according to my Ford shop manual is for "Accessory Feed, seat belt warning, swing tilt column, safety convenience door ajar, low fuel, power window safety relay feed."

I have a 69 with standard interior, no factory tach, and none of the fancy warning lights that it lists.

That slot only has 1 clip, the other side of the fuse clip is non existent. Also non existent is the "Accessory Post" terminal and associated wiring according to the drawing.

So, I don't see any reason why I can't use this to power my gauges by getting another clip with a wire soldered to it.. Or perhaps they make a special clip for this reason?

Auto meter suggests using a inline 4 amp fuse to each gauge, so I figure I could throw a 16 or 20 amp fuse in place. According to the writing on the fuse block and the book, that slot is good for 20 amps... I am also thinking about powering my radio off of this as well.

Looks like it will work but Im am just asking this in case somebody knows something about it that I dont see.. Im not the best at electrical work.

Do you guys think it will be alright to use this slot to power

Is there a clip or something made to replace or attach a wire to the second side of the fuse I will add?

Im thinking of just getting a clip and soldering the correct gauge wire to the other end for now.. I do plan on getting the American Auto wire kit at some point in the future.

Here is a picture which shows what Im talking about

 

[j69302]

Well i was able to figure it out.. found a fuse holder at radio shack which also had a 3/16 male bladed connector on it which I can connect a wire too.

Temporarily wired it in and it all works... now I just have to tee off my oil pressure sensor and run the wires to the sending units.

 

[robbz28]

I hope by "tee off" your sending unit you mean add an additional sending unit for your new gauges. If you run 2 gauges off of one sending unit that don't always work...for me anyway, I may have been doing something wrong. I bought a sandwich adapter that goes between the block and filter that gave me 3 extra oil pressure ports, one for my original gauge and one for my mechanical gauge (never trusted an electrical over the mechanical)

 

[j69302]

the stock gauges run on about 6 volts from the Instrument voltage regulator.. aftermarket ones are 12volt..

plus the sending unit for the stock gauge is most likely a different resistance range than what an aftermarket one uses.. might be the same, maybe not.

I am t-ing off my oil pressure extender and going to have both my original and then my autometer to back it up because all my gauges work and I want to keep the factory ones, but have some more accurate ones as well..

 

[robbz28]

Yeah...i thought about Teeing off of the original....but as I mentioned earlier, I got that sadwich adapter and I just love it. I also opted for the pillar gauge pod....I like it...but I hope one day to get the whole aftermarked gauge bezel with the auto meter gauges installed.

 

[robbz28]

Just wanted to comment, i like the way that you added the power to the fuse box...but on my 67 (not sure if yours is the same) there is that accessory post on the back of the ignition switch that has 12v switched power, all you have to do is put an eye on the end of your wire and go straight to it.

 

[robbz28]

My bad...i just read that your post is missing....and that 69's dont have the post on the back of the switch. I think that post is usually threaded in, so if there is a hole where the post is supposed to be, i bet a small piece of all thread might restore your old post. Anyway, very cool job if you got everything to fit properly.

 

[j69302]

My bad...i just read that your post is missing....and that 69's dont have the post on the back of the switch. I think that post is usually threaded in, so if there is a hole where the post is supposed to be, i bet a small piece of all thread might restore your old post. Anyway, very cool job if you got everything to fit properly.

I could have gotten a post, and screwed it in.. Everything was there in the fuse block except the post and the other half of the fuse clip. But that piece I found at radio shack was much simpler.

I got my oil pressure sensors TEE-d off.. was surprisingly easy, took about 10 minutes.. Put my new temp sending unit in my my thermostat housing( original one is still in the intake manifold) and temp wired everything in and it all works.

Now I am just waiting to receive my DIN-Radio bezel so that I can fit the front end of my center console to the dash and mount the gauges in the console underneath the dash.

Here is the hardware I used to tee it off and the result. Had approx 40psi at idle and anything off idle and above stayed at 50 psi. .. I always wondered what it was actually running at.

 

[j69302]

Oh yeah only last thing to figure out with the wiring is where to tap off for the light power.

Im scared to tap off the light switch because I had my original one smoke for some reason, then replaced it and had the replacement one burn up. They both failed at the "full bright" end of the resistor, when the wire stopped coiling and contacted the pad which turn the dome light on.

I think i ended up fixing it by re soldering that connection that burned up.. This was 10 years ago so i dont remember and I dont know what caused it to burn up. I suspect the horrible alarm that the previous owner put in which tapped into everything.

It was a Genuine FoMoCo light switch. I bought a second one just in case and am holding on to that.

So my options are tapping off the fuse, the switch, or the wire which ran to the light bulb for the original radio which is currently capped off. It kind of a small wire though.

and tapping off either 1 of those places is going to add the same load to the circuit so I don't know.

Each gauge has a #161 incandescent bulb in it.

 

[mustangmutt]

Using the lamp feed to the Radio should work fine to illuminate the gauges.

 

[j69302]

I used the lead to the radio lamp.. Tested it, worked with the headlight switch in both parking and headlight position. It also worked for a while having it temp mounted. (electrically all connections were the same from temp/perm mounting)

Now after permanently mounting, with all the same connections, the gauge lights only work in the parking light position.. When the switch pulled full aft for the headlights, the new gauge lights go off. (no affect on the factory cluster, works correctly both positions)

I don't understand this.. Anybody have any ideas?

Is there a internal breaker on the light switch? i would think if there is and that is blown, then my dash instrument lights would not work either.

I been out of town since I permanently mounted it and won't be able to physically look at anything for a while but I am trying to do some brain storming right now.

 

[mustangmutt]

Is the wire you tapped into a light blue with a red tracer? It makes no sense that it would go out when the headlights were turned on and the other gauge lights continue to work.

 

[j69302]

umm.. It was dirt colored.. haha.. With a light socket at the end.. It worked before when it was all temp installed... Im baffled why it doesnt right now.. Ill scrape the dirt off when I get back home.

 

[tx65coupe]

I also have no idea why the illumination would only work with park lights on and not with headlights on. Are you positive that it worked that way before permantently installing? That really doesn't make sense.

Nice work. I did something similar so I could keep my OIL warning light on my Falcon style cluster. I spaced mine farther out from the motor so its easier to get to the fuel pump.

Since we are talking about oil, get rid of that Fram filter and get a Motorcraft FL1A or a Wix or Purolator.

Do I spy some RMP motor mounts and a MD clutch cable? I have the same parts on my car.

 

[j69302]

Im pretty sure it work both positions, but now that I think about it I am wondering that myself... The previous owner had a aftermarket radio in there when I bought it, that wire and light socket were taped up from the day I bought it.. I assume it went to the original radio.

Ill verify the color of the wire when I get some time this weekend hopefully..

Worse case Ill just move it over to the heater lamp wire, that works correctly. I also have a new original ford made headlight switch i might throw in there just to see if it makes a difference.


I usually use fram tough guards if I cant find the motorcraft one.. I noticed the oil stay lighter color longer with tough guards.. I have read all the stuff about them though.

And yes those are RMP mounts and MD clutch cable

 

[j69302]

Took a look at it.. The wire I used was a black with yellow stripe.. Looked it up on a wiring diagram and it said it was Ignition switch illumination.

So where exactly would that go? I have standard interior.. Is this something left over in the harness that was meant for the deluxe interior?

I couldnt find the blue-red wire for the radio light, but I ended up just tapping off of the heater light wire.

 

[mustangmutt]

That is odd, the only circuit I could find that showed a black/yellow wire is from the P terminal on the headlight switch that feeds the front park lights. It will turn off when the headlights are turned on. All gauge, radio, clock, dash, control illumination is a Blue/Red wire that will dim and brighten when the headlight switch is on and you twist the knob.