General Automotive Wiring

Ok, first off, what I'm going to propose is big, ugly, and definitely not 'high-tech'.

But it's the result of seeing what works and what doesn't in 2-way radio installation in public service vehicles; it's ugly, clunky, but it's rugged and reliable.

1) Go to a large electrical supply house and buy as many bakelite single fuse holders for NON-30 style cartridge fuses as you have accessories. About a buck or two apiece, including the fuse.

2) Mount them as close to the + terminal of the battery(ies) as possible.

3) From the battery side of each fuse holder, run a # 10 wire, ring terminal crimped plus soldered, to the + cable as close to the battery as possible.

4) Bare the cable, and use a 'split-bolt' connector to hook all of the fuse block feeds to the cable.

5) Tape the connection well.

6) Run feeds to each accessory from the other end of the block(s), fusing with an NON-type cartridge fuse of proper size.

7) If you need to have a large-current accessory activated by IGN, go to your nearest Motorola 2-way radio shop amd ask for a # 59-813764 power relay. When you get this beast in-hand, you will see 4 terminals. The two together at one end are the coil. The other two are the contacts. Run one of the coil terminals to IGN, the other to ground. Run power in at one of the two remaining terminals, and out the last one. It is rated at 30 amps, and that's a very connservative figure.

8) If you have more than one IGN-controlled device, use the first power relay to turn on all the rest, that keeps draw thru the IGN switch down.

9) All terminals carrying currents over 5 amps must use ring terminals, crimped + soldered.

10) Never, NEVER run a wire thru the firewall or other metal partition without a rubber grommet. The Motorola shop will have those, too.

As I said, this is how I did it for 10+ years on police cars, ambulances, fire trucks, and other emergency vehicles.

It's ugly but it works, the fuse block terminals are self-cleaning when you remove and insert a fuse, and the best part is that the fuses are cheap (under a buck)!

First, make sure you have some zip-ties, and a bunch of different consumables (big word we use at work that means wiring accessories such as T-taps, male/female spades, ring terminals, etc.)

Mount all the hardware first. drill all the holes, blah blah.

Now step back and think to yourself what the cleanest route to each accessory would be. I usually use the *stock* firewall gromet to route me wires into the engine compartment. I noticed you said that you didn't want to tap into the battery wires, or use the battery terminals. In this case, I think your best bet would be to essentually make your own fuse box under the dash. This can be achieved by simply getting several inline fuses from a stereo shop or Radio Shack and neatly placing them together and mounting them in an inconspicous place. Now you must decide if you really don't want to run wiring to the battery. I really don't recomend T'ing that many connections to the wiring under your dash. 1 or 2, ok. But anymore than that gets messy and dangerous. Maybe it would be easier to understand if I just told you how I would do it.

I myself would simply T into the main positive wire (usually 4-6 gauge) with the appropriate splitter. I would then run an 8 gauge wire from that splitter into my cab through the firewall gromet I mentioned earlier. Use zip-ties to neatly secure the wire to anything that you want unless, of course, it moves or gets hot. Now, under the dash where you just ran the wire through the firewall, simply connect your inline fuses to that and run your accessories from there.

For driving lights, it's a different story. I did it the simplist way. Connect the positive wire from the passenger side driving light to the positive wire on the passenger side LOW-BEAM, and do the same for the drivers side. Then run a ground wire from each driving light to a good grounded area, I used a clean section of the bumper support, which is completely hidden. To protect the wiring from the weather, I simply covered it in weather proof wire-loom that you can get at any good stereo install shop. This way you have driving lights that are 100% legal and automatically turn off and on(OFF with high-beams), without mounting a toggle switch.

Do the same thing with the backup and clearence lights, that way you can forget having 32 toggle switches on your dash, and don't have to worry about them.

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---------------------------------------------------------------- Ed Murray Certified Locksmith My Enthusiast's Website:

So if I understand this right, there is a large fuse, say 4 smaller fuses (in my app) and then 4 more smaller fuses?

I have some 30a relays in hand. Not that it means anything, but the switches that came with the accessorys are I believe 20 and 25amp (the switch is 15). I have one (on a different truck) installed with a

25amp switch and it runs a little hot. But I have some better connectors and I was hoping that the relay would help.

So for 4 switched accessories, 5 relays? Brings me back to my a.p days.

Have an assortment of these myself.

One last K5 question: Has anyone remounted the stock bat/oil/temp sensors elswhere? The steering wheel, while thin, is always in the way. If so, how so?

~LGM

Want the switches. I have also read that back up lights (in my case some small white fog lights) can over load the reverse light circuit. I'd also like to be able to "flash" people who refuse to turn off their highs. Basically I want to be able to control all of these whenever I want.

Basically I am thinking I am going to get one of those screw-on terminals that allows aux hook ups to the batt. Attach a heavy-gauge wire to that, and run it inside. Then I'll pick up a 4 fuse fuse box and run my accessories off of that.

No ideas on how to make my switches dim with my interior lights?

-The Lonely Grease Monkey

1985' K5 305CUI TH700R4 NP208 KJ's successor

"Ignorance is preferable to error; and he is less remote from the truth who believes nothing, then he who believes what is a wrong." - Thomas Jefferson

just a warning... most states have laws against "white light" from the rear of a vehicle unless you ARE backing up or unloading cargo.... probably not a big deal if used carefully, but if they're looking for a reason to pull you over and they see you flash someone behind you with white light, they can use that as a reason to pull you over...

Mac

Same law with driving (fog) lights. They shouldn't be on if your high beams are on. Some brights are bright enough without adding more to it. But if you just want a short burst of light to shoot at someone, go ahead.

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---------------------------------------------------------------- Ed Murray Certified Locksmith My Enthusiast's Website:

Instead of running a long high current line into the cab how about using relays located near the controlled lights. Mush better and will lower the voltage drop to the lights, It also means less heavy wiring into the cab with less potential for a short. Plus the backup/work lights could be connected to the back-up switch with a relay and work automatically while being able to be switched on/off for other uses. You will also want to make sure your lights are legal in aiming and mounting, many are not and those cause others to get pissed due to being blinded. (the flashing of the backup lights or high beams in the front is not legal, if you do it and the person is so inclined you can be arrested for "aggressive behavior".)

Anyway. by using relays you can set up the lights so you can turn them on/off when not needed, I would also connect them inline with the high/low beam circuits so that you could just leave them switched on and they will go on/off with the correct lights (driving lights with high beams and fog lights with low beams)

Yes officer, I always use reverse to slow down on the highway. :-)

The white light thing is actually done in the inspections around here, and colored light that shows white light (IE a cracked lens) will fail you.

But it would be used in good taste, I really wish I wouldn't have to use it at all to tell you the truth.

-The Lonely Grease Monkey

1985' K5 305CUI TH700R4 NP208 KJ's successor

"Ignorance is preferable to error; and he is less remote from the truth who believes nothing, then he who believes what is a wrong." - Thomas Jefferson