36 fuse block fuse blowing

[36and63]

After installing my wiring harness ( 6 volt) in my 36 pickup I installed the battery to see if she would turn over and she did. I then gave her some choke and she started right up. I have had the engine running before but not since installing the new harness. I took it down the road and she ran real well and then drove it back into the shop. Since I have no headlights in the truck yet I went and installed a new plug and light on the drivers side only A couple hours later I try starting it again but can see it isn't wanting to fire so I made sure she had fuel etc. still no firing and then I see that the fuse in the fuse block has blown so I remove it and install a new one to only have it blow immediately. Since it was fine before the headlight plug install I remove it and put it back to the way it was. I then install another fuse but it blows again. I'm trying to understand what has changed that is causing the short I seem to have. Just a brief going over electrical harness plugs hookups etc. all looks correct. it seems in order but clearly must have a short and not sure where to begin. Any suggestions appreciated.

Thanks,
Pat

[rotorwrench]

You really need a multi-meter to check the conductor wires to ground. Start out by isolating all but ignition to make sure that that circuit is good. If it is, check each follow on circuit for short to ground with a multi-meter set to check resistance or beep for continuity. Touch one probe to the wire end and the other probe to the frame. Any isolated circuit that checks to have continuity to ground will be the one to check the conductor wire for damage in its run from buss to load (electrical component) or buss to switch & switch to load.

[36and63]

Thanks rotorwrench for the feedback and information. I noticed that if I remove the ammeter loop hooked to the fuse block the fuse no longer blows so I'm going to trace that back since it hooks to the battery side of the starter switch to rule out that it might be pinched, will check as you advise too.


Pat

[JSeery]

If the stock arrangement the fuse has nothing to do with the ignition circuit. The fuse is for lights only. If you have a lot of stray wires unconnected I would start by looking at them.

[JSeery]

Originally Posted by 36and63

I noticed that if I remove the ammeter loop hooked to the fuse block the fuse no longer blows so I'm going to trace that back since it hooks to the battery side of the starter switch to rule out that it might be pinched, will check as you advise too. Pat

If I'm following what you are saying, removing the ammeter wire to the fuse block removes the hot power lead and there is no way for it to blow. Are you using a wiring diagram? That might help sort out the circuits. One thing you could check is remove everything from the light circuit side of the fuse block (with the ammeter wire connected back up to the hot side) and see if it will start.

[36and63]

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I was able to account for every wire except horn wires ( not connected) wired according to my 36 wiring diagram everything seems in order. I will try removing everything from the light circuit side as you recommend leaving the ammeter wire hooked up to see if she will start. Just really frustrating to install the complete harness and it started immediately this morning. Its been a long day but I will need to retrace everything down again.

Thank you Jseery for the input, electrical is where I struggle!

Pat

[rich b]

If you put a light across the fuse, it will light until you find the short. Saves blowing a lot of fuses. Sorta like the giz pictured. I have alligator clips more suitable for glass fuse holder on another similar tester. The inline fuse is not necessary when used in this manner.

[36and63]

I took and hooked up a 6 volt lantern battery to energize the coil and she fired right up, as soon as I cut the connection she stopped. Now going back to this morning I turned the ignition on she fire up, when I was finished taking her for a run and pulled in the garage and turned the ignition off and she stopped as it should. I set my multi-meter to check continuity on the ignition switch and its beeping on or off? How would it have worked initially?

[JSeery]

You should only have continuity in the on position, it is a switch and makes contact in the on position and breaks contact in the off position. If the switch remained in the contact position for a period of time it may have damaged the coil, points, etc. Depends on if the distributor happen to be in the points open or points closed position. What is a little strange here is the ignition switch should have nothing to do with the fuse blowing.

[36and63]

I seen where the generator cutout relay wire connects was touching the steel cap which is screwed to the generator case. I removed the cover, inserted a new fuse and it no longer is blowing and she started right up as it should. I turned it off via the ignition switch and it worked. I then turn the ignition back on and started again without issue.

Pat

[JSeery]

Cool