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Testing electrical system w/o engine

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sypherzero

15+ Year Contributor
461
7
Feb 14, 2008
Marion, North_Carolina
So I'm wondering if I can test the cars electrical system without having an engine or any of its sensors installed. I'm wanting to check basic functionality of some of the electrical components (windows, sun roof, lights) to see what I need to buy, because I bought the car as a bare shell and I have no idea what works and what doesn't. Can I simply hook the starter into the wiring harness, and ground the negative side to something on the chassis, hook up a battery, and turn the key to acc? If not, is there another way? Any advice is greatly appreciated!
 
do not need the starter. Just hook the battery up and should be able to test power windows, seats, lights, wipers.
 
I was in the same situation one time and wanted to test the power seat for example. The connector i disconnected from the power seat motor had Black and Red wires so i used small battery clamps with wires and i touched on the pins momentarily directly negative and positive to the connector. The power window motor usually has same connectors, simple power, ground,etc.
 
Leave starter out. Battery negative to chassis (eg. firewall). Put a 10 amp fuse in series with battery positive (in case there are shorts so you don't burn up the wiring) and connect to the fusebox with all fuses in. If there is no fusebox, connect to anything that has a positive wire that would go directly (not through a relay) to a fusebox common bus (which other things are also connected to - thus you will power them). Be aware that fuseboxes have fuses to protect separate circuits. So if there is no fusebox, then there's no fuses. So the wires for individual circuits would stop there and not connect to other circuits that would be on other fuses (and possibly not even to other circuits on the same fuse if they don't arrive at the missing fusebox or are not connected to them). See wiring diagrams to see what circuits are connected together on which fuses.
 
Right, the starter doesn't need to be connected at all or the wire connecting the starter to the battery which will also connect the alternator in most cases. Just connect the fuse box to B+ and ground to chassis' and everything should work as if the car is running. And a battery charger wouldn't be a bad idea as you have no alternator to keep it charged.
 
I apologize for not getting back to this sooner, and thank you all for your responses! One more question, would this be the positive connection that goes to the alternator that I would hook the battery to? Sorry if I seem ignorant, I'm not very good with the electrical side of cars.

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Yes that's the positive feed for the alternator. You can usually have your alternator and starter bench tested for free at a good car parts store.

And to be a little more help, there are two large gage white wires coming out of your fuse/relay box that will combine to one eye loop connector. This connector goes to the positive side of the battery. This is what is going to feed basically the whole car, windows lights etc. You will not need to hook up the starter to test out the rest of the car but is not a bad idea to make sure you don't have any other issues.

One other piece of advice I can give is to make sure you have a good ground for the car. Once your engine is in place you should run one small ground from the firewall to the intake manifold and one large ground cable right from the starter bolt to the fire wall.

Hope this helps
 
Yes that's the positive feed for the alternator. You can usually have your alternator and starter bench tested for free at a good car parts store.

And to be a little more help, there are two large gage white wires coming out of your fuse/relay box that will combine to one eye loop connector. This connector goes to the positive side of the battery. This is what is going to feed basically the whole car, windows lights etc. You will not need to hook up the starter to test out the rest of the car but is not a bad idea to make sure you don't have any other issues.

One other piece of advice I can give is to make sure you have a good ground for the car. Once your engine is in place you should run one small ground from the firewall to the intake manifold and one large ground cable right from the starter bolt to the fire wall.

Hope this helps
That helps a ton, thank you!
 
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