Electrical Troubles...HELP

Today I was going to try to start my Bronco after a long frame-off restoration. I can't get the motor to turn over. I'm definitely not an electrical genius so I need some help. Here is what I did electrically during the restoration.

new battery
new battery cables
old alternator
old starter
new Pertronix Ignitor
new Pertronix coil
all old switches except the emergency flasher switch
I "rewired" using an economy wiring harness. I have a feeling this is where my problem lies.
new starter relay
new voltage regulator
Everything else is original except a new steering wheel with a new horn switch.

Here is what happened.
I got everything hooked up and my last connection was the + battery cable. As soon as the cable was touching the battery, I heard an arcing sound. I chased it down and found it coming from the steering column. I removed the new steering wheel and found the horn switch completely melted. When I installed the horn switch I didn't pay any attention to how the switch was connected. I just plugged the two prongs into the two wires and called it good. Did I do something wrong here???

I disconnected the horn switch and tried to continue from here. I turned the key and nothing happened. Here are my observations:
headlights - working
headlight dimmer switch - working
parking lights - working
emergency lights - working
turn signal indicators - not working
heater - not working
wipers - not working

So I decided to chase down the electrical path and see where it led me. I started with the starter relay. I disconnected the starter motor lead from the relay and touched to directly to the + battery post. The starter turned over and cranked the motor. So I know the starter motor is OK.

Then I touched the + battery post of the relay to the terminal on the front of the starter to bypass the ignition switch and nothing happened. I pulled out my multimeter and did some checking.

The battery was reading 15 volts from post to post. With the ignition switch in the off position, the potential from the + battery post to each of the relay terminals on the starter relay and the + post on the coil was 0 volts.

With the ignition switch in the run position, the potential from the + battery post to the relay terminal closest to the starter motor lead was 15 volts. The potential from the + battery post to the relay terminal closest to the battery lead was 0 volts. The potential from the + battery post to the + coil post was 15 volts.

With the ignition switch in the start position, the potential from the + battery post to each of the relay terminals and the + coil post was 15 volts.

According to the wiring schematics, I am seeing with the multimeter exactly what I should be seeing.

It seems like I should see the starter motor turn over according to what the starter relay is doing. I took the starter relay off and reinstalled the old one. I came up with the same results.

I think I found one thing I did incorrectly when I "rewired" using the economy harness. There is a wire on the harness that is supposed to run "to ignition switch run terminal". I think I accidentally connected it to the A terminal on the ignition switch instead of the C terminal.

Any ideas would help out. I will switch the ignition switch terminals tomorrow and see if that makes a difference. Does anyone have any other ideas?

Thanks,
Scott

OK, so as I said before I'm not an electrical genius. I was reading VAC instead of VDC. That is why my original post was showing 34 volts. I changed everything to 15 volts as tested this morning. I still need help though. Any ideas?

Scott

Make sure the relay is grounded I chased that problem for half a day one time...

The black (-) meter lead should be on the negative battery post or other good ground.

15volts in a battery is way way high. Do you have:
1.) A cable going from the battery positive to the relay. Should have battery voltage both ends all the time.
2.) A cable going from the opposite side of the relay down to the starter. Should only have voltage with the key in the start position.
3.) A small wire going to the relay "S" terminal that has 0 volts except when the key is in the start position.
4.) A wire going ot the "I" terminal that has potential for ground. Test with one lead on battery + and the other ot the end of the wire and you should get a voltage reading.

If you wont start you are missing one of these 4 things.

Sounds like you melted some wires to the starter solenoid also..!? 15v?? do you have a charger hooked up to it??

Mike732...Good point. I installed fiberglass fenders and I think I ran grounds to everything. I definitely need to check the starter relay.

RRRAAAYYY2...
1.) Got it.
2.) Got it, except there is no voltage with the key in the START position. That is what I am trying to figure out.
3.) Assuming that the S terminal is the one closest to the battery cable post then there is 0 volts from the + battery post to the S terminal at all times except when the key is in the START position. Then it reads 15 volts.
4.) Assuming that the I terminal is the one closest to the starter cable post then there is 0 volts from the + battery post to the I terminal when the key is in the off position and 15 volts when the key is in the ON or START position.

NOTES:
* I am getting all of these readings with the red cable on the + battery post.
* I am getting these readings with a cheap Harbor Freight multimeter ($5). So there is a large possibility that it isn't reading completely accurately. It is reading about 14.5 volts. I just rounded it up to 15 volts. But it will still tell me when there is voltage and when there isn't.

I need to check the ground again.

Any comments on my notes here?

Scott

Is the starter solenoid mounted to metal or does it have a wire running from its metal mounting tab to ground?

The starter solenoid is mounted to the fiberglass fender. I need to check to see if I ran a ground to the solenoid. I know I ran one to the voltage regulator.

I am a bit confused, for 3 and 4 you should have one end of the test lead on the - of the battery, the other on the terminals. Regardless we can do some backyard tests to narrow this down.

1.) Disconnect the I terminal (righthand side) make a small jumper wire from the I terminal to the - of the battery. Try starting the truck. If this doesnt change anything go 2.

2.) Leave the first jumper in place and disconnect the S terminal on the solenoid. Take another small jumper wire from the battery + and lightly tap it against the S terminal. This should cause a spark and the motor should crank, so be prepared for both.

3.) Try putting the I terminal wire back on the solenoid and using the small jumper lead from + battery to the S terminal again.

answers: If the motor cranks when trying number 1, then the wire from the solenoid I terminal to the coil is not connected properly. If you have an aftermarket ignition and this wire is remove, you can terminate it at a known good ground.

If the motor cranks during number 2 and 3 then the wire leading to the S terminal is defective. It may have voltage but not enough amperage to do anything. Time to start tracing it back.

If the motor cranks only during step 2 then both wires going to the solenoid are defective.

If none of these gets the motor to crank, you have a defective solenoid.

Also if you just hear a heavy click during any of these tests, that counts the same as the motor cranking as far as the above tests go.

I found out last night that the starter solenoid is not grounded. Maybe this is my problem. I didn't have a chance to run a ground and try to crank it. I had to prepare for this ice storm we are having. I'll run a ground to the starter relay and check to make sure the ground on the voltage regulator is good. I tried #2 this past weekend with a screwdriver bridging the battery cable to the S terminal and nothing happened, but I still think that is attributed to the non-existant ground.

I'll try that tonight and let y'all know what happened.

Scott

It has to be grounded for the relay to pull in...Mike

mike732 said:

It has to be grounded for the relay to pull in...Mike

Click to expand...

You would think that I would have thought of that first too, doh. Good call.

I grounded the starter relay last night and tried to crank it up. Again nothing happened, but it was so cold last night that I went inside. I couldn't stay outside long enough to do any troubleshooting. I will try again tonight and see what I come up with. I'll post tomorrow. Thanks for everyone's help so far.

Scott

scottmcwms said:

I grounded the starter relay last night and tried to crank it up. Again nothing happened, but it was so cold last night that I went inside.

Click to expand...

So you ran a wire from the negative battery terminal to the mounting tabs on the starter solenoid? If so, then make a small jumper wire and touch the +BAT connection on the solenoid to the small " S " terminal, next to the +BAT connection. This should at least cause the solenoid to click.

I would definitely clean the ground terminals or any other terminal that is not new with a wire brush. This was my problem once, and somebody suggested that I do that, and that was the problem. Just passing along a tip.

RRRAAAYYY2 said:

I am a bit confused, for 3 and 4 you should have one end of the test lead on the - of the battery, the other on the terminals. Regardless we can do some backyard tests to narrow this down.

1.) Disconnect the I terminal (righthand side) make a small jumper wire from the I terminal to the - of the battery. Try starting the truck. If this doesnt change anything go 2.

2.) Leave the first jumper in place and disconnect the S terminal on the solenoid. Take another small jumper wire from the battery + and lightly tap it against the S terminal. This should cause a spark and the motor should crank, so be prepared for both.

3.) Try putting the I terminal wire back on the solenoid and using the small jumper lead from + battery to the S terminal again.

answers: If the motor cranks when trying number 1, then the wire from the solenoid I terminal to the coil is not connected properly. If you have an aftermarket ignition and this wire is remove, you can terminate it at a known good ground.

If the motor cranks during number 2 and 3 then the wire leading to the S terminal is defective. It may have voltage but not enough amperage to do anything. Time to start tracing it back.

If the motor cranks only during step 2 then both wires going to the solenoid are defective.

If none of these gets the motor to crank, you have a defective solenoid.

Also if you just hear a heavy click during any of these tests, that counts the same as the motor cranking as far as the above tests go.

Click to expand...

OK, so I finally had a chance to follow through on these suggestions.
The motor cranked during number 2 and 3 so I did some continuity testing of the S and I wires (I just checked the I for good measure). I found that the S wire was good. So I did some more checking. I pulled the fuse on the wire that feeds power to the ignition switch and checked for battery voltage. I didn't find any. I pulled the fuse box off the wall to look at the back of it and took a picture of what I found. I also took a picture of the wiring diagram that came with the wiring harness.

Here is the email I sent to the tech support group that sold me the harness:

I am having trouble getting my Bronco to start. I can't even get the starter relay to close and send power to the starter motor.

Please look at the attached wiring diagram you sent me. I have marked a few areas that I terminated. Is the white wire supposed to have constant battery power? It is marked to go to the coil +. The problem I am having is getting power to the ignition switch. I ran the white wire to the ignition switch "B" terminal. I guess this is wrong because I looked at the back of the terminal block (second picture I sent you) and the white wire only has power when the "ACC" block has power. That wouldn't do much for the coil when you are starting.

Do I need to run one of the constant power wires to the ignition switch "B" terminal.

The big red wire (constant power supply) is connected to the battery via the fusible link.

The big yellow wire is connected to the ignition switch "ACC" terminal.

Thanks for your help.

Click to expand...

The big yellow wire that goes over to the right side of the block is the headlamp switch lead.
The red and yellow wires that I referred to in the email are on the left side of the block

So the question is, Am I crazy or should the white wire (coil +) have constant power.

I think this is my problem and why I can't get power to the S terminal on the starter relay to close the relay and start the motor.

Let me know what y'all think.

Scott

Lack of power to the coil doesn't have anything to do with the starter circuit. The wire for the "S" terminal comes from the ignition switch. Depending on your harness it may be routed through a place for a Neutral Safety Switch (NSS). The NSS are usually found on vehicles with an automatic transmission, but your wiring harness may not differentiate. I would think that there should be instructions on how to deal with the NSS, or lack of one.

I think it would be cool if you could make a drawing or scan the scymetic so i can follow you better. OR this is a great time for some anti theft devices. If you ever wanted to do a hidden switch thing to start your truck, now is the time. My favorite is an extra geadlight knob on the dash. Run power through it to the wire feeding the S terminal on the solenoid. It might not cure any of the unyet detected probelms in the new harness, but it will get you running and keep people from hot wiring your truck.

OK, I figured everything out. The response I got from the wiring harness vendor was that he accidentally sent me a copy of the diagram of the older version of the wiring harness. Int the newer diagram it correctly represents the white wire as a switched wire instead of a constant power wire. I ran one of the other constant power wires to the B terminal on the ignition switch and everything works great. RRRAAAYYY2 thanks for the "backyard checks". That is what helped me figure out that something was wrong with the power supply to the ignition switch.

The engine turns over great now. Now if I can just get the puel pump to get fuel up to the carb. That's an easy solution, I hope!

Not a bad idea with the anti-theft device.

Thank you everyone for your help. I was already starting to look into the Painless or Centech harness to eliminate the problems. I didn't want to do that from the start because they cost so much.

Scott