2007 Dodge Charger 3.5L V6 won't turn over, but starter and relay appear to be working

Question

Some quick background: This is my cousin's car, it has been parked for over a month, at some point before it was parked my cousin hit a tree (no airbags or anything) and afterwards it would start but not stay running. Not sure exactly at what point it stopped starting, but I came in the picture after someone else changed out the starter (some auto parts store guy apparently who left before confirming he actually fixed the issue). At the moment, when the key is turned you can hear the relays click (and I can feel the starter relay click) but the starter never even attempts to spin.

Anyways, I came on the scene today to try and help out. I first manually turned the engine over a bit to make sure it could actually turn over. Then I got under the car and took a look at the starter. It does look new but I noticed that the little signal wire wasn't connected to that little spade connector on the starter. I hooked that up but it didn't help. I then rigged something up to provide 12V to that spade-looking pin (jumped between the 12V terminal on the starter relay to that little signal pin) and when I just supply 12V directly to that pin, the starter spins and engages the engine. To me that rules out the starter and battery as the issue. We took out the starter relay and tested that for continuity/actuation and it all works as expected. We just jumped the contacts that the relay typically connects and doing that spins the starter and engine as well. We tested the 20A and 5A ignition fuses in the fuse/relay box under the hood and those all work fine and have power to one side when we take the fuses out.

So it seems like the issue is somewhere else but the simple wiring diagram (attached) in the Haynes manual I bought doesn't show much other than what we tested. It shows some inputs to the PCM/ECU but I'm not sure how I would be able to test any of that. From looking online I have seen that the ignition switch may be the issue but I don't see how that ties in on the wiring diagram either, plus the relay is clicking and works so I don't see why the engine/starter won't spin.

I guess I am stuck because we can get the starter to turn by just jumping the relay, we have confirmed the relay works, and the relay appears to click when the key is turned. However, the starter never spins when the key is turned, so I'm not sure what I am missing. I can't really check what the PCM/ECU is thinking so there may be some other condition that isn't being met but I am not aware of it.

Any ideas? I would like to help out my cousin and save him the cost of a tow to a dealer plus their diagnostics and get him his car back. Thanks in advance!

Answer 1

Remove the starter relay from its socket and connect a 12v bulb (something like 5w) across what would be the relay coil contacts in the socket. You should be able to just push some wires into the socket connectors, or do a better job with crimp-on spade connectors.

If when you turn the ignition the bulb lights brightly, then clearly you have enough current flowing to operate the relay.

If this works, and if as you said jumping the switch side of the relay makes the starter turn, then the the starter relay is clearly at fault.

Update after finding out that you have swapped relays:

With many automotive relays, it is possible to pop the case open and operate them manually. You could try opening the relay and watching to see if the relay is getting fully energised. You could also give some manual assistance to see if when the contacts close properly that the starter motor turns.

Answer 2

the relay appears to click when the key is turned

You hear a click -- how do you know it's the starter relay that's clicking? There are other relays in the car. Put a meter on the starter relay terminal and ground and see if it's getting 12V when you turn the key to the start position. If not, you are hearing a different relay's click, not the starter relay. That would suggest an issue with the ignition switch or with a fuse related to the ignition switch.