No Start and Car is "Positive" Ground

[dmc8163]

Hi. I have a 1970 Dodge Challenger R/T.  The car was running fine but this week I decided to remove and repair the Tach and Clock.  After repairning them I returned the gauge cluster to its place in the dash and put everything back in order. The old axiom that no good deed goes unpunished starts here. I tried to start the engine without success by making three 20 second cranks. The next time I cranked the engine the entire car lost power.  When I attached my test light to the negative battery terminal and touched the probe to the engine it lit up!  Now I'm the only one I know with a "positive" ground Challenger.  What would cause that?  I've checked all the fuses, the grounds and fusible link.  All appear fine. Can you tell me the likely cause of this situation and where to start looking to repair it?  I admit to being "challenged"  when it comes to the electrical system.

[72rtchallenger]

you should probably pull your dash gauges back out and start there,,sounds like you shorted something to ground,,are u sure its hooked up right? maybe u crossed a hot and a ground wire?,,since thats what you made repairs,, it may be the best place to start

[jimynick]

Running on memory here because I haven't gotten into the dash either, but, it seems to me that there's an ammeter in the dash that carries the full current across it. I know most people are converting them to voltmeters which are much less dangerous. 1-disconnect the battery NOW, 2- as mentioned, pull the cluster, 3- check your wiring against a good schematic, because it seems that you've got a circuit reversed polarity-wise, somewhere. 4- go buy a lottery ticket, because the average guy who'd done that would be looking at the smouldering ruins of his car. 

[tommyg29]

was the car restored in England by chance!? 

[MEK-Dangerfield]

When you removed the gauges, I assume you removed all the wires as well. Something isn't connected right, or your tach wasn't rebuilt right.  A short in the tach will cause a no spark situation at the coil.      You might want to check that your fusible link wasn't fried also. 

[dodj]

Normally the battery negative goes to the block and the block is tied to the frame (firewall). The battery -ve is also connected to the body close to the rad. If those wires are all in place, you will not get the readings you posted. However, if you get all those wires connected, you will blow something - fusible link or fuse. But it will give you a place to start looking. 

If I were you I would remove the cluster again and check to make sure the wiring is intact and not pinched somewhere.

[the_engineers]

Disconnect your battery and put an ammeter inline to make sure you're not passing current while she sits.  You could have a fire if the fusible link didn't blow.

[mopar12372]

your test light is just completeing ground .  soooo you have a bad graound that easy.

[dmc8163]

Thanks everyone.  On my way to pull the dash again. Will continue to look for grounds. D

[Chryco Psycho]

I agree you have a bod ground between the negative battery terminal & the block