05 f150 electrical problem. Starter.
 

I went to drive to town the other day and noticed my speakers were not putting out any sound, this happened once before, also when it had been raining a lot, but it fixed itself. But I continued to town.
When I got to town I turned off the truck and heard a loud bang like the starter hitting the flywheel.
So I went to start the truck again to listen to it. But when the key hit the accessory position, the truck started, that's before the key got to the start position.
I turned the truck off, BANG.
Turned the key to the accessory position, truck started. I could not hear anything wrong while the truck was running.
I disconnected the battery for a while and gave the terminals a good cleaning, it didn't change anything.
I left the truck in that parking spot for a day. It's a dry place. The next day the truck started properly, but the speakers still didn't work.
The next day the speakers started working again, but now it has a check engine light.

Any ideas?
Thanks!

You need a scanner to see what the codes are. Maybe a bad ground. It's hard to tell without more info.

If I take it to a mechanic and find out what the codes are, would that work? Does it make more economic sense to just buy a scanner?

If I were you I would just buy a scanner they are relatively cheap. I have a cheap one and I have an edge programmer which is a scanner also. But yeah we need to know what codes to help you diagnose the problem.

Most auto parts chains will put a scanner on your vehicle and read the codes for free.

p0506

IAC curcuit condition or idle speed higher/lower than expected.

ECM has detected that the IACcounts are higher/lower than expected. the engine speed is not in expected range.


possible causes
vacuum leak on engine
dirty throttle body
IAC motor defective
poor electrical connection to the IAC valve

The guy at the auto parts place didn't think this made much sense.

And now the check engine light is gone.

This really sounds like a wiring or grounding problem -- more than likely grounding -- in my opinion (not to be taken as expert).

When a ground is poor, you can get mysterious issues like yours. For instance, if one part of your truck is properly grounded, and another part isn't, the voltage levels between the two will be incorrect. How much they vary depends on how poor the ground is.

Many local libraries ( around here, and probably elsewhere), have online versions of alldata. Usually, alldata will have a section showing location of all of the vehicle grounds. You will likely have to look this up in the library itself.

Also, you can poke around the grounds you know about with a meter. See if the voltage varies more than a few tenths of a volt from one end to the other -- or to the frame when you turn on various electrical loads.

Good Luck, things like this can be frustrating because they're often intermittent.

hj

An update. And I'm going to look for this specific problem, maybe start a new thread.

After the last heavy rains, the truck wouldn't start or anything at all. Battery read 7 volts. I looked for a short, and found one. Followed that through the firewall to the fuse box under passenger side dash. Where I isolated the problem *in* the fuse box, which turned out to have a bunch of water in it. I'm no expert. But I'm pretty sure the fuse box inside the truck is not supposed to contain rain water. After I dry it out, I just need to find the leak.