No crank no start

SHELBY5150

MEMBER
2008 DODGE MAGNUM
3.5L
V6
2WD
AUTOMATIC
145,000 MILES

Recently when I got into start it and leave it started just fine and I went to turn the lights on because it was dark and noticed that they were already on without the switch being turned. (Not automatic headlights.) So, I then looked at the dash and the lights were on but none of the gauges worked, or the brake lights, or the blinkers, and where it displays the miles said "no bu5." I continued to drive it and it drove fine and after about 15 blocks everything started working again and the blinkers worked and all. It only did that one more time after that and has not done it again. A few weeks later is when it would not start anymore. Now when u turn the key to ACC position it dings, the dash comes on the gages work but as soon as you turn to the start position it does nothing at all. No noise no clicking no nothing. If you could please help me in the right direction I would appreciate it. Thank you

Thursday, December 30th, 2021 AT 5:07 PM

3 Replies

JACOBANDNICKOLAS

MECHANIC
110,176 POSTS

Hi,

Anytime there is an electrical issue, I start at the primary source, the battery. Have you checked to make sure it is fully charged, and the battery terminals are both clean and tight? Also, when you turn the key to the start position, do the dash lights or gauges turn off and then come back on?

Here are a couple of links to get us started. The second one is a basic load test for the battery. Follow the links and let me know the results.

https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked

https://www.2carpros.com/articles/car-battery-load-test

Also, let me know if you tried jump-starting it.

Let me know what you find or if you have other questions.

Take care and Happy New Year.

Joe

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Thursday, December 30th, 2021 AT 11:51 PM

SHELBY5150

MEMBER
15 POSTS

Yes, I have put five different batteries all connected to cables and another running car. Yes, the dash lights come on the while attempting to crank they go off until you release the key then they come back on.

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Thursday, December 30th, 2021 AT 11:55 PM

JACOBANDNICKOLAS

MECHANIC
110,176 POSTS

Hi,

Let's dig into this a bit. Did you check to see if it will start in neutral? Also, if you look below, I attached the schematic for the starting system. I had to cut it in half to make it readable for you, but I did overlap the two.

First, check to make sure fuse 8 in the under-hood fuse box is good as well as (again) fuse 8 in the power distribution box in the rear of the vehicle. Confirm they are both good and both have power to them. Here is a link you may find helpful:

https://www.2carpros.com/articles/how-to-check-a-car-fuse

If both are good and have power, then remove the starter relay in the integrated power module (fuse box) under the hood. If there is another one that has the same part number, switch them to see if it changes things. If there isn't one, here is a link that explains how to test a relay.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

If the fuses are good and the relay is good, then I need you to get a helper. Have the helper put the ignition in the start position while you check for power at the smaller wire on the starter motor. That should only have 12v in the start position. Also, looking at the wiring schematic, it could be one of two colors. (Yellow wire with a gray tracer or a light green wire) Please review pic 2 below.

The red wire should have 12v at all times.

Let me know what you find.

Take care and Happy New Year.

Joe

See pics below. Note: Pic 3 is the under the hood fuse box and pic 4 is the rear fuse box. Both fuses are fuse number 8.

Images (Click to make bigger)