Hey guys, ive been chasing a no crank issue for a few days and could use help before throwing more time/money at it.The
car was driving fine, parked it for about 30 minutes and when i went to start it back up, nothing no crank, no noise at all. Assumed starter or relay, however after confirming the relay was fine and replacing the starter (bench tested before installing it works), the only difference is now there's a slight hum sound, but still no start or crank. Ive been chasing it and have done as such so far
-Battery tested
-Starter wires seated properly
-replaced battery terminal clamps
- Used a test light and confirmed the starter works while installed and under load.
- And before you say RCM its already been resodered previously, and I'm getting a noise while trying to start, so i dont believe its this.
Hearing the hum i believe the starters engaging but not fully mabye low current? bad power delivery?
Im sorta just stumped any and all suggestions or tips are greatly appreciated.

 

It is not only the solder joints on the RCM that fail. It is also the relays as they age. Just sayin

 

How old is the battery?
You can search on how to check the manufacturer's actual date code on the battery case.
If it's over 3 years old, I would replace it. Without the enough power, the car will not start.

 

less than 6th month old as stated in the original post battery tested at the proper voltage, also replaced terminals so im sure its not a battery issue, jump pack and normal jump attempted with zero results. Thank you for the tip though.

 

Get in car, put key in, turn to start.
If starter does not engage, relax the key to "ON", wait 45 seconds.
If the engine cooling fan is running at high speed, it is the RCM. End of discussion.

If engine cooling fan is NOT running at high speed, it can be a low battery, but it is very likely an interlock issue.
Interlock issues vary between automatics and manuals, as they have differing criteria to engage the starter.

Determine the outcome of the above test before proceeding.

 

First, RCMs are electromechanical items, they fail more than ANY OTHER module in the car. If you have not put in your known-good spare RCM, (or done my test above), you don't know that it is not the RCM. MANY of us carry a spare, because they are EASY to change,they are prone to failure and because they are cheap. NO 12 volt relay lasts forever and the RCM has two that must activate to start the engine.

Second, the "noise" can be the blower or the secondary air pump or the motor in the throttle body. You only can use the 'noise' as a diagnostic once you identify the noise.