Not Firing, Again

[1970heavychevy]

Would a short in my turn signal switch or headlight switch stop me from getting spark?


I replaced my distributor cap, button, module, plugs and plug wires to fix something. I removed my wiring harness to address another problem and when I put it back in my headlights stopped working. I toke the switch apart and cleaned it still not working but noticed when I bumped the turn signals my horn blew. I saw a little spark at the switch. So I know there is a short. But no spark at the plugs.

I'm almost ready to push it off a cliff!

[1970heavychevy]

Would a short in my turn signal switch or headlight switch stop me from getting spark?


I replaced my distributor cap, button, module, plugs and plug wires to fix something. I removed my wiring harness to address another problem and when I put it back in my headlights stopped working. I toke the switch apart and cleaned it still not working but noticed when I bumped the turn signals my horn blew. I saw a little spark at the switch. So I know there is a short. But no spark at the plugs.

[Robert8096]

If it'a an HEI distributor then you only need 12V switched to it. Check the wire going into the distributor from the harness for 12V. I would say that you have a few wires crossed

[1970heavychevy]

The wire going into the HEI plugs into the fuse box on the engine compartment side. Is that where it goes?

[kcjones]

That's correct, HEI 12v should draw from a wire connected to the fuse block. However, I've heard before that a coil power wire (which our trucks have stock) is not 12v. Check out the diagram below..if you're using the stock 20y wire from the starter solenoid, it won't work correctly for the HEI. You may consider running a new power wire from the fuse block to the HEI connector (make sure it's ignition switched of course) to rule out some of your problems.

[1970heavychevy]

I have that diagram but am very rookie at wiring. Hell I'm rookie at most of this. The wire going into the HEI is white, not factory, maybe 12 or 14 gauge. I don't know if it's switched. But it was working, then I changed my header gaskets and spark plugs (R45TS gapped at .045). Then went on to try and fix the headlights by cleaning the switch. Went to crank it and no spark.

[Longhorn Man]

Nothing in the headlights or column will prevent the truck from starting.
On your headlight peroblem... since you were just down there messing around in that area... check the plug for the dimmer switch. If it is unplugged, the lights won't work. Wiggle the plug and see if that does it. If not, then step on the button a few times... if still nothing, then kick it from the side... all while checking the headlights or an assistant telling you if they come on and/or flash on for a second.
Your horn... you'll need to pull the steering wheel (special remover you can get at any parts house for not much money) and possibly just tighten the levet, but more likely, the switch parts need replaced. That's why the horn hoks. You are grounding out the horn ring.

[kcjones]

If it's white, you're right - not factory. Do you have a voltmeter/ammeter (whatever you call the gadget that detects current)? If not, they should be cheap, but you'll definitely need one. Establish first if you're getting 12v at the hei connector power pin before any other troubleshooting of the no spark problem. The headlight, horn, dimmer could take you a long time...

If you've got your 12v at the hei connector, then you've got a module/cap/rotor problem (seems reasonable as you just replaced the module, right?). Once you get your spark back, start tracing out your headlight issues - the voltmeter is your friend, check your circuit at every junction through it's path.

[kcjones]

Oh, yeah, and don't be intimidated by wiring. It gets tricky on newer vehicles because there are so many harnesses, and they're all hidden, but on our trucks, every wire is visible. Just remember electricity is always trying to be grounded, and everything electrically powered is just like a dam over a river - when the water flows, the wheels move. Always start at the beginning of the circuit, and move your way towards the thing that uses the juice. In the case of the headlights, verify you have 12v coming into the switch, and when you switch it, that you also have 12v out. If it's still not making it to the headlights, it's simply in the harness or the wires themselves.

[Luvlegs]

If you took any of the junction blocks apart when you worked on the harness, make sure the connectors didn't get bent over or pushed back so they aren't making contact.

[1970heavychevy]

I went ahead and pulled the engine compartment harness apart and just wired the basics for it to run. No lights up front at this time. No turn signals. Only break lights. I've also been through the cab harness three times and got rid of not needed stuff (dome light, dimmer switch, heating and air wiring, even windshield wipers). I've tattooed the wiring diagram to my brain.

[Longhorn Man]

you removed the dimmer switch? Did you bypas it?
Like I said above, if the switch is unplugged, the headlights won't work.

[jostrans68]

i had the same issue it was the pickup coil

[smoked68]

I getting ready to say the same thing, Pickup coil, or little yellow wire underneath that you cant see is almost broken,and it will run for a while then die. Oh but when you check for spark it would give me spark, then crank. Then 15 minutes into the cam break in just shut down.....Yeah pick up coil or "the wire". My guess

[kcjones]

Longhornman is on it - no dimmer switch, no headlights. Make sure you've got power into the headlight and dimmer switch, and out of both (if switched on, of course). If both are true, then you're on the right stuff...harness, wires. Or, skip it and buy a relay kit so you can run high power headlights. The relay setup will still need the headlight switch to work (to turn the relay on), but at least you will be forced to go through all the related wiring to get it working.

On the firing, didn't you say you're not using the yellow wire (the factory coil wire)?

Good luck and let us know how it comes out!