Beginner electrical question
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Tuned
Joined: Sep 2018
Posts: 364
Likes: 22
From: Eagar, az
Beginner electrical question
Howdy all. 1973 f100/fe390 here so been having an over weekend parasitic draw problem for a few weekends now if truck wasn't ran till Monday. Charged up newer battery, and went to hook up cables, and as soon as I touch the second cable, the starter solenoid engages with it's click. Starter hasn't been stuck on at run at all. Just a few day parasitic drain. And haven't noticed anything else. Could this be my drain, or something new? I'm found it by trying to do a draw test with my multi meter between neg batt cable and neg terminal. I know this is probably a dumb question, but I am electrical illiterate
Cargo Master
Joined: Jul 2015
Posts: 2,063
Likes: 137
From: tucson
Things to try: If you're not going to drive it for a couple days, disconnect the solenoid and see if the parasitic drain continues. You could also try removing fuses to see if you can narrow down the draw, that way.
Fleet Mechanic
Joined: Jul 2013
Posts: 1,996
Likes: 236
From: NE Ohio
Put your dmm in series with the ground strap. You will see any drain if there is one.
Disconnect ground strap, put 1 lead on the battery the other on the strap. It won't tell you what is draining but it is a start.
Than start with the fuses, leave it on the battery, and pull fuses while checking if the drain stops.
Disconnect ground strap, put 1 lead on the battery the other on the strap. It won't tell you what is draining but it is a start.
Than start with the fuses, leave it on the battery, and pull fuses while checking if the drain stops.
Thread Starter
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Tuned
Joined: Sep 2018
Posts: 364
Likes: 22
From: Eagar, az
Tried running multi meter in series with ground, but as soon as the circuit is complete( from batt pos through entire system back to batt neg post) the solenoid snaps into engagement. No key in ignition. I had a prob a year or so ago with ignition switch burned out, and solenoid getting stuck on crank after startup in run position. Switch feels loose inside again. Gonna temporarily hook up a different ignition switch a buddy has to see if this is the culprit, as no way to have any testing electricity without engaging the solenoid at the moment. Does this sound good? I've been through 5 solenoids in past 4 years, and 3 ign switches in same time
Fleet Mechanic
Joined: Jul 2013
Posts: 1,996
Likes: 236
From: NE Ohio
solenoid should not be engaging doing this.
All you're doing is making a bridge between the ground cable that was connected to the battery and your DMM that is now connected to where the ground cable was connected.
If it's engaging do that, well I don't even know what would cause that and you should have that battery disconnected all the time before it burns your truck down.
All you're doing is making a bridge between the ground cable that was connected to the battery and your DMM that is now connected to where the ground cable was connected.
If it's engaging do that, well I don't even know what would cause that and you should have that battery disconnected all the time before it burns your truck down.
Logistics Pro
Joined: Jul 2005
Posts: 4,217
Likes: 154
Tried running multi meter in series with ground, but as soon as the circuit is complete( from batt pos through entire system back to batt neg post) the solenoid snaps into engagement. No key in ignition. I had a prob a year or so ago with ignition switch burned out, and solenoid getting stuck on crank after startup in run position. Switch feels loose inside again. Gonna temporarily hook up a different ignition switch a buddy has to see if this is the culprit, as no way to have any testing electricity without engaging the solenoid at the moment. Does this sound good? I've been through 5 solenoids in past 4 years, and 3 ign switches in same time
Thread Starter
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Tuned
Joined: Sep 2018
Posts: 364
Likes: 22
From: Eagar, az
Have that. I have way overkill on ground straps probably. Got a box of 15 of em at a garage sale a few years ago, and just went to the hilt grounding everything from bumper to bumper. Ign switch my buddy had did not fit but will have one sometime today and at the parts store. Along with a new solenoid. I always hear about the poor quality of solenoids these days, and they aren't lying. This will be #5 in 4years of daily driving. Same with the ign switch. Only been on the truck 6-7 months if that. Without knowing how to test it, I'd say it's toast, as it has a burnt smell, and alot of play compared to when it was new
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More Turbo
Joined: Nov 2018
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From: CA
Easy enough to check the solenoid with test light or voltmeter. It has battery power going to it, if it isn’t going to ground or past it your problem is elsewhere.
If the solenoid was engaging it would send power to the starter.
If the solenoid was engaging it would send power to the starter.
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Tuned
Joined: Sep 2018
Posts: 364
Likes: 22
From: Eagar, az
It's not spinning the starter though. Just a loud click when batt cable touches the battery, so I figured the ign switch is letting power past it somehow. It's on hold at the moment due to the foot of snow I got hit with this afternoon. Really wish I had a garage or workshop I could sit her in and tinker on it with a wood stove going.
More Turbo
Joined: Nov 2018
Posts: 563
Likes: 143
From: CA
The solenoid is just a switch or relay, the click should be it closing which sends power through it. If it works(closes when ignition turned to start) I’d be looking elsewhere for your problem; but hey it’s good to have a spare on hand.
Disconnect the main cable to the solenoid then repeat your test.
Disconnect the main cable to the solenoid then repeat your test.
Thread Starter
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Tuned
Joined: Sep 2018
Posts: 364
Likes: 22
From: Eagar, az
Hmm. I just figured it was bad, since I have never heard it click like that when reconnecting a battery. Done it dozens of times without that happening. Nothing usually is what happens when I touch the cables back to the batt
FTE Legend
Joined: Nov 2015
Posts: 30,828
Likes: 4,094
From: Angier, NC
To see if the switch is sending power to the solenoid as you think might be happening pull the small wire going to the S lug and test the cable to battery.
If it still clunk pull the I ther small wire to the I lug if it has one and try again.
If either one stops the clunk that is what is sending power back to the solenoid but the I lug wire shouldn't have power unless running or cranking.
Could also take your meter to test each wire for power wher disconnected from solenoid.
As for the solenoid I take it you keep getting the same one from the same store and wanting a different out come?
Go to NAPA and get their top of the line solenoid not their cheap line one..
Make sure it is grounded good to the inner fender when you mount it..
Report back on the clunk as thst needs to be fixed b4 we track down the power draw.
Dave ----
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Tuned
Joined: Sep 2018
Posts: 364
Likes: 22
From: Eagar, az
Dang. Still clacks with either, or both wires ( I and s ) pulled. New ign switch/solenoid did nothing for that. Haven't tested wires for power yet cause it's damn cold out there today. Could it be the starter shorted, or doing something funky? I checked all grounds, and cleaned em up as well. Does this even mean there is a short somewhere? I assume power to solenoid would be an open circuit somewhere. But why isn't the starter spinning when the solenoid gets energized? I have no clue, and really appreciate the knowledge this site has going on.
Lead Driver
Joined: Nov 2006
Posts: 5,217
Likes: 506
From: Pa.
Dang. Still clacks with either, or both wires ( I and s ) pulled. New ign switch/solenoid did nothing for that. Haven't tested wires for power yet cause it's damn cold out there today. Could it be the starter shorted, or doing something funky? I checked all grounds, and cleaned em up as well. Does this even mean there is a short somewhere? I assume power to solenoid would be an open circuit somewhere. But why isn't the starter spinning when the solenoid gets energized? I have no clue, and really appreciate the knowledge this site has going on.
More Turbo
Joined: Nov 2018
Posts: 563
Likes: 143
From: CA
As before . I’d double check that’s where the sound is coming from because it doesn’t add up
the solenoid is a switch. Battery power hooks up to it, if it works power doesn’t go through unless the s terminal gets power(ignition turned to start as designed). If power goes through it the starter spins. if power doesn’t go through it the starter will never get power and not be part of any circuit. A test light or voltmeter will verify this in a few seconds but really isn’t necessary.
the solenoid is a switch. Battery power hooks up to it, if it works power doesn’t go through unless the s terminal gets power(ignition turned to start as designed). If power goes through it the starter spins. if power doesn’t go through it the starter will never get power and not be part of any circuit. A test light or voltmeter will verify this in a few seconds but really isn’t necessary.