jluquette

My antenna had stopped going all the way down for years - don't use it much so who cares? Then it got stuck all the way up and it started to really bother me. The motor was still making appropriate noises for about the right amount of time so I figured that it was just the nylon tail that had broken. Sure enough, I took the external trim off the outside, turned on the radio and then pulled the tail out - it was broken about a foot from the mast. Ok... so ordered a new mast on internet. Took out the motor assembly, disassembled it and removed the broken tail. Put everything back together and reinstalled the motor assembly. Everything going OK so far. Mast came in a couple of days later... had my brother sit in the car and turn the radio on, stuck the tail in the hole (teeth toward the rear) and turned the radio off. Sucked it right in and everything seemed to be fine. And, everything IS fine... EXCEPT that when the antenna goes up to very top, the motor continues to grind for about a half a second like it would still be trying to push the mast up slightly beyond its full height. When the mast is pulled back in, the motor stops immediately - like it should. Anybody have any idea what's going on? Is it possible that the mast that I bought is slightly too short - and maybe there's a sensor inside that thinks it should go up a couple of more inches? The mast that I bought was advertised as compatible with my car - which is a 2004 SC430. Anybody knows exactly how tall the fully extended mast should be? Are there different lengths of masts that I should have noticed? I'm afraid that the metal motor gear is going to strip the plastic tail pretty quick if I don't get this figured out.
Thanks for any suggestions.

ShawnOk

iTrader: (1)

I've been doing a lot of antenna work recently and there's a TSB on this, which I found on this forum. There's a specific protocol in order to install a new mast in order to avoid the problems I believe you are having... have a look. I believe by pressing the "AM+Disc," it causes the motor to unwind fully. Then you put in the nylon so it starts at the proper place on the nylon (like Point 0 of the nylon meets Point 0 of the motor gear). At least that's what I'm lead to believe from my research. Hope it will solve your problem.

jluquette

OK, thanks a bunch! As I wrote in my initial post, I did not follow this exact protocol - because I didn't know it existed. Now that you have pointed it out - I can't wait to get home from work to try it.
I'll post whether it worked or not tomorrow.

texsexlex

iTrader: (3)

...mine was actually doing this when I replaced it with an aftermarket mast. I noticed that after it fully extended, it would retract about an inch or so, then the motor would stop.I thought it may have been adjusting to the radio signal/strength. But after a week or so, it never did it again ...no problems or issues since

tromly

wishing you luck with your repair!

jluquette

OK, I'm back. Tried following the TBS exactly and after doing this it does exactly the same thing (that is - grinds for about 1/2 second after reaching the top). It's been a couple of weeks now and it shows no sign of re-calibrating itself. It does retract a few inches after reaching it's full height, but that is just adjusting itself for FM (which is shorter than AM). When fully extended on AM, it is exactly 34 1/2 " from the base nut to antenna tip. Could someone measure an original Lexus SC-430 antenna at maximum AM height so that I can convince myself that the mast is not about 2" shorter than it should be? I'd really appreciate it.
Thanks everyone,

Joe

jluquette

Hey, just decided to order another antenna and see if maybe I just got a bad one. While I was looking at the antennas on E-Bay, I noticed that an Optional 42" mast exists. Couldn't find anything else about it though. Is it possible that I may have had one of these as original equipment? Anyone know where these 42" antennas were used?
Thanks again,

jluquette

Well, I ordered a new "OEM" antenna from another company and when it came in, I looked at it and could find no difference between it and the replacement that produced the grinding noise. So, I didn't have too much hope that it would make a difference. I changed it per protocol and I couldn't believe when it went up and there was NO grinding noise! I wish I could explain it so that we might all learn something but I just can't. One worked and the other didn't ... and that's all I can say.

sprcarrera

Yep my aftermarket antenna makes the same grinding noise. I'm used to it so I don't even really notice it any more. But if it ever breaks, I'm definitely replacing with OEM.

PJohn54

Guys, I am new to the forum and was wondering if changing the mast is easy. Mine is stuck in the down position.

tdedden

PJohn, my antnenna motor makes the whirring sounds as if it's trying to extend the antenna however it remains in the retracted position so I'm assuming that the motor is fine and only the mast needs replacing. Based on some of the earlier postings in this thread it looks like an OEM antenna is the way to go. I printed the Lexus technical bulletin and am going to save myself about $200 that my local Lexus garage wanted for their "labor".

mpezely

Replacing the Antenna
This is a two-person job.

•Remove the antenna retaining nut. Be careful not to scratch it.
•With the key in the ignition switch "LOCK" position, press the "AM" and "DISC" buttons on the radio simultaneously with turning the ignition switch to "ACC". Then the radio "LCD" display will read "ANT" and the antenna mast will hyper-extend, disengaging the cable. You can let go of the "AM" and "DISC" buttons now.
•With the ignition switch still in "ACC", the new cable is inserted to a full stop into the motor antenna assembly through the mast pipe hole in the body panel, with the teeth on the antenna cable toward the rear of the vehicle.
•As the person in the driver's seat switches the key to "LOCK", feed the cable and mast pipe in.
•After it retracts completely, replace the retaining nut