Tech Article
Ron Francis Wiring
Grounding Guidelines

Grounding Guidelines

If you don't want to run ground wires for these items you had best make sure they have a clean unpainted, un-corroded ground

horn (s)
gauge (s)
headlight switch
some wiper switches

1st- The battery MUST be grounded to the engine. NO! Not the frame and then too the engine. Ever see a factory car with the battery to the frame rather than direct to the block? Sure their front mounted batteries. What about the original engine in your old car?

2nd- The frame and body must now be grounded to the block. Same bolt or area of the block is best. The shorter the path the grounds must pass thru steel and iron,  the better

3rd- Steel is just as good you say? Consider this, Copper is the best conductor used in an automobile. Letís call that 100%. Brass is only 22% and steel is only 16%, quite a loss? Yes, If I told you the starter was working on about 9 or 10 volts, youíd fix it quick? I think you would. Well, itís working on a lot less than you think , so fix it.  Battery to block, block to frame, block to body.

4th- What about the items mentioned above. IF they have a GOOD ground. Great. They might already be working. Did you clean the metal bare? Yes, rust is actually better than paint. You donít mind scratching the rust off but you hesitate to clean off the paint?  Must do...

5th- Gauges, lights, etc? On a steel car they might be OK. On Fiberglass cars it is a must to use a full grounding system. Most new cars are now getting full ground systems even with steel for good reason. Ever have a high beam indicator glow a little even when on the low beams? How about a taillight that doesnít seem as bright as the other? Replaced the bulb and it didnít fix it? Bulbs are either good or bad.  No half bright. Have a turn signal that flashes faster on one side than the other? You have it...

6th- Switches? Steering columns? Why ground a switch or steering column? The headlight switch has an interior light switch built into it.  If the switch isnít grounded, that part of the switch canít work. WIRE WORKS includes this ground wire. Trouble shooting calls have dropped significantly with this improvement

Steering columns? They have a switch for the horn. It closes the circuit to ground to operate the horn relay. No ground no horn. Bolting it into the steel dash will usually work. Not always and never if the mounts are against fiberglass or in rubber.

7th- Wiper switches often work off a ground also. Newer (1960 to 70's stuff)

8th- Gauges and Lights, like high beam indicator or turn indicators and interior lights need a good ground.  Headlights , taillights and parking lights need a ground, you knew that.  Did you know that if theyíre dim or operate funny they need a better ground?

Gauges always need one except ammeters and hopefully I talked you out of that a long time ago. Still using one? Call me.....

9th- Using our GW-15 grounding terminal block is great for these smaller items. The block has a heavy feed wire that is
connected directly to the battery or mounting bolt on the block near the starter. The starter is usually closer and completes the path with a heavier wire. Grounding directly to some battery terminals allows corrosion to built up on small wires which is more critical than just the heavy starter cable.

10th- The braided cables work good from the block to the frame and body both. Nothing should be over looked. You can run too many fuses but never too many grounds.

.Grounding headlights, especially Halogen bulbs to the bucket or fender is almost always an eventual problem

Electric fans draw buckets of juice. A separate ground wire to the central system location can keep you cool in more ways then one

You should take advantage of any accessory with a separate ground lead. Rather than shove this under a mounting bolt, run it to the central grounding area.

Horns are usually OK grounded to the steel body or frame.

Central grounding location makes troubleshooting great.

Electric fuel pumps and gas senders are usually easiest grounded to the frame. A separate ground to the central location is better

Master disconnects are best installed in the positive cable. This is especially important with electronic accessories or fuel injection

Typical battery locations require grounding the battery to the engine block and then a back up rear ground to the frame near the battery

Aluminum transmission and starter housings can sometime create electrolysis (corrosion) with dissimilar metal like brass battery cable lugs. It is best to run the ground cable to the cast iron block.

Use the engine as the primary ground connection and attach the frame, central grounding terminal strip and steel body to the same stud if possible.




Copyright 1999 - 2005 Hot Rod Hot Line All Rights Reserved
No Portion May Be Used Without Our Written Permission
Contact Us Toll Free (877) 700-2468 (US) or (208) 562-0470 (Outside US)
246 S. Cole Rd, Boise, ID 83709