Just like it says. Is there a way to test all (or the majority) of the electrical components w/o a motor installed? I'll be buttoning the interior and almost everything else up this and next weekends. The motor/tranny won't be ready for another month. I was hoping to check lights, signals, radio and other electrical operations so I can fix any issues while I'm waiting on the horses to arrive.

What would I need to connect/ground to get things working? Also, since there's no engine, there's no alternator either. If that's critical I could hook it up and set it on the A-arm.

Putting parts back on is much better than taking them off and fixing them. I can start to see the end in sight!

('69 Vert)
Thanks
Scott

 

You can use an ohmmeter to check just about every wire in the vehicle. Battery disconnected from the system. Consider that all electrical wires are just trying to send a 'signal' from one place to another...either passing a voltage or connecting a ground. All your ground wires need to be properly connected.

The difficult part is keeping track of everything you test...and then assuring that you tested everything. Get a good...and complete...schematic to work from. Then start at the positive battery wire and check resistance from that wire to the next connection point in the circuit. It should read "0" ohms which indicates that the integrity of the wire is good and the wire is routed properly. Also checking from that wire to ground should check "infinite" resistance; otherwise there would be a short in that line (if it also checks "0" resistance, or unless there is something like an electrical component or light bulb on that line. Once a section of wiring has been fully tested, check it off on your schematic and continue with the next wiring downstream of your prior test. When you finish that circuit and finally get to a ground point, you can move to another circuit. Keep that process going and, eventually, you will have checked all the wiring in the car. And, you should know where any problems were found. It is best to fix each problem as you find it...so that it might not affect any other circuit negatively. But, you don't have to do it that way if you don't choose to. You may also want to put some kind of a mark or peel-n-stick colored dot at the locations where you connect your positive lead for each test. This way, you could visually identify any points that you have not checked. Of course, then you have to go back and remove them when you get done; or you'll have a lot of little paint dots, if you used a paint stick for that purpose. Anyway, it's something to consider.

Once you get going, you'll get the hang of it and it will go faster. Just try to stay 'error free' when making your tests and keeping your records as to what you've checked and the results you got.

Good luck with that task!

 

Man that sound simple, but tedious...

I was hoping for something more along the lines of "connect pos batt cable to red starter cable, ground the grounds on the frame and ensure the alternator connections are isolated so they don't short the system."

Any chance of something like that so I can turn on the lights, signals, radio, etc to actually see the components working? ALL the wiring in the car has been replaced except the dash harness, but that was replaced 2 years ago before I bought the car.

Thanks for the reply. That sounds more like checking the integrity of a suspect harness to me.

Scott

 

Hi Scott.
Although I had the engine in but not running I also tried to do a preliminary electrics test. Start with the test light first and no fuse for clock, courtesy lights, ... If it comes on you have a short, if not woohoo and you can continue. I used a 12v power supply hooked up to the + & - cables in the tray. This will power up most things which don't require alot of juice. Ofcourse with the engine out your bat + cable is not connected to the starter and the other harness wires. So in order to use the battery to power things up you'll need to connect this cable with the others which go on that starter lug. Maybe you'll find some usefull things in this thread I wrote, maybe not.
Nick
http://forums.corvetteforum.com/c3-g...r-rebuild.html

 

Sure you can but you will have to think it through and be careful.
Hook everything up like you think it should go , except for the neg battery cable.
Turn everything off and close passenger door
Open drivers door
Put a 12v bulb type test light between the neg battery cable and neg battery terminal
Light should be lit because the drivers door is open
Close drivers door
Light should go off,meaning no shorts to ground.
At this point I would replace the test light with a jumper that has a 20 amp fuse in line
Now you can test any component that is under 20 amps
If you feel confident everything is OK you can up the fuse to 30 ,if your feeling really *****'y you can connect the neg battery cable.

 

You've got the right idea, that's all you need to do if the wiring is all new. Also make sure the wires that are normally connected together at the horn relay junction point are connected and isolated from ground.

 

"That's all you need to do" IF the harness is made correctly, you didn't make any mistakes, no wires are crossed (improperly swapped with other wires), etc. The whole purpose of using an ohmmeter is that it won't do any damage when checking the wiring. If you hook up the battery to do your testing...and there is a short somewhere, that line of wiring is fried and you will have to repair that wire (or, if the insulation catches fire, replace the whole thing).

Test with an ohmmeter--no damage if problems are found; test with a battery...well, it will do the testing for you--but you won't like the result if there are problems. Do as you will...

 

I really appreciate everyone's input on this topic. I guess I'll take the cautious route that 7T1 mentioned at the beginning. I DO NOT want to fry any of my new harnesses. I guess I was feeling impatient. I'll take my time and go methodically. I'll have to do it in the mornings since it's topping 110F today.

 

If you use the 12v testlight method you won't fry anything.

 

Unless there are damaged areas or alterations or modifications to the new wiring, the fuses, fusible links, and circuit breakers will protect the circuits, that is what they are there to do. No need to ring everything out, total waste of time in my opinion.....but hey, what do I know, I've only been an electrician for 25 yrs!!

Do whatever you feel comfortable with. I went through this when I did the body off resto on my car, I used a 12v power supply to power up the car to test everything out as I put it back together. A little common sense goes a long way; make sure you have all the connections made to the proper items, and any loose connections isolated from ground or each other.

 

Plus using an ohm meter almost everything will ring to ground.

 

Well, I got the motor and tranny installed and I'm ready to get things working.

Some successes, some stumbling spots...

I triple checked all connections and that all my grounds were good. I connected the battery and let it sit for a few minutes and walked around with a flashlight to make sure there wasn't any smoke and rechecked the fuses. I next turned on the hazard lights (never worked before, no flasher) and they worked, including my fiber optics. Score!

I then turned the key to ACC and turned on the new radio...found one of my speaker connections was grounding out (stereo went into "protect" mode). Fixed that quickly and got the stereo working. Score!

Turned the key to RUN and the seatbelt light came on and reset w/ the button. Tried the turn signals and they worked (signals and fiber optics), but I got no indication on the dash. Point Car.

I turned the parking lamps on, then the headlights on. The headlamp warning light came on (no vacuum to open the doors right now) and the speedo/tach backlight came on. Setting the parking brake activated the BRAKE light in the tach and turning on the high beams activated the BRIGHT light in the speedo. The A/C control lights and cigarette lighter lights came on and the cigarette lighter began heating when I pushed it in. Score!

I then spent the next 30 minutes going through the settings on the stereo and jamming to some tunes.

I haven't gone any further tonight (already lost a gallon of sweat in the garage).

So, the only stumbling block I've found is the turn signal indicators. Everything else seems to work so far (including my rear defogger).

Any ideas on what could be causing the indicators to not work even though everything else is working? I checked all the bulbs before putting the dash back in.

With any luck, I'll be cranking the car on Saturday or Sunday. Man I miss driving it (been since Feb).

Thanks
Scott

 

ttt