FM Fine, AM Static

Got all OEM wiring from the antenna into my head unit. FM radio sounds perfectly fine, but the AM radio is all static. Any suggestions for how to troubleshoot this? The antenna plug and wire on the head unit end looks fine, and is plugged in tight. The antenna, wiring, and ground on the exterior of the vehicle all look fine, and everything's tight. I don't have outer fender liners, but there's no indication of any physical damage to that stuff.

 

most of us just stop listening to am radio!

what kind of radio do you have?

 

I use AM for sports when I'm out of range of the FM station and/or don't have a cell reception for iHeartRadio. Happens pretty much whenever I'm camping in the Sierras or the Coast Ranges.

It's a Pioneer MVH-S600BS, which is a very basic HU. Got it about 4 years ago.

 

I’d check the base of the antenna at the fender. I remember a thread similar to yours, a few years ago (can’t find it), that showed the base corroded and causing reception issues.

 

Are you talking about the base of the ground, or where the actual cable hits the tube? (Should've re-taken that first photo after I cleaned it off, in retrospect.)

 

Not that, other side off the fender. The base of the antenna mast, that’s where it was.

Tried another search - found it.
https://www.tacomaworld.com/threads/antenna-corrosion.817076/

 

Interesting. I'll have to pop that off tomorrow to take a look.

 

Been busy and haven't gotten around to this yet, but... how do you pop that rubber (plastic?) cap off without damaging the paint? There's not really a gap that I could stick a plastic trim tool in, and the only video I've found of it has the guy completely destroying the cap in the process of removing the antenna.

 

Not really sure. I’ve never needed to. Maybe a parts diagram would shine a light?
*edit*

Looks like the screw point for the mast comes out. The chrome ring holds the nut that holds everything down, maybe? That thread I linked had no hints? Sorry I’m of no more use.

 

No sweat. The first photo in that thread shows the cap removed with the antenna still attached.



@Jessel, any tips?

 

I should really do this on my truck. I've only been without good AM & FM reception for about 6 years now..

I believe the one above was damaged. Seems like the mast comes out, then the 4-slotted nut, then the bezel will pop off. I think..
https://www.tacomaworld.com/threads/how-to-replace-oem-antenna-in-fender.261341/

 

Ah. That would explain a lot.

 

@SR-71A explained it a heck of a lot better than my back-asswards brain did. Thank you sir.

 

Finally got around to trying to pop the cap off, used the proper 4-prong tool on the antenna nut and couldn't remove it (stripped, and was just spinning), and then decided to temporarily put the antenna back in. Of course, the antenna snaps in the assembly while I'm threading it back in, so I guess I'm replacing everything anyway. SMH.

 

Months later, I got around to cutting the cap off and replacing the ground with wiring, cap, cap nut, and antenna (all OEM), and... FM works, but AM doesn't. There was some corrosion, but not a ton. Trying to decide if I want to try swapping out the internal line (through the dashboard) between the head unit and the new ground line, or just spring for a new head unit.

 

Ordered the antenna cord sub-assembly, hooked it up, and... no change. So I guess that means I need a new head unit. Meh.

 

The AM antenna is separate from the FM antenna. The AM antenna is usually a loop of wire contained inside the radio. I'm guessing yours has become disconnected. You'd have to pull the radio to check.

 

I wish I'd realized that before tearing everything apart, except for the head unit. I guess I'll take a look at the guts on Sunday.