Hello everyone, I recently purchased a 1997 LX450 in November of 2022. When I purchased the car the radio was dead and I sourced the problem to a blown amplifier. I replaced the amplifier and the radio worked again and I noticed that multiple speakers were blown. I replaced all four of the door speakers with aftermarket speakers that fit in the OEM speaker covers with the same resistance as the factory speakers and they sounded glorious. However, less than 24 hours later the replacement amplifier blew while I was driving. I then replaced it with another used amplifier and did not play the radio at all. However, since the amplifier is getting constant power from the ignition it ended up blowing again at some point. I checked the resistance for all of the speakers at the amplifier connector and they are drawing the correct resistance. No fuses have blown and every other function works on the car as it should except for the radio. I really am at a loss for what the problem is at this point and am considering replacing the radio and buying another amplifier. I want to stick with the OEM/stock head unit and set up which is why I don't scrap for aftermarket. Has anyone seen a problem like this? I would really appreciate your help.
Dead radio, Blown three amplifiers. At a loss. Please help (1 Viewer)
- Thread starter LC450IME
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It sounds like you know somewhat what you're doing, so I don't think it is user error. I also don't think that it is the fault of the speakers, or the power source. In my experience, a problem on the input or output side (power supply issue, or incorrect impedance from speakers and/or wiring) will cause immediate problems. It doesn't happen eventually. Maybe someone else has had personal experience with this. But when I installed aftermarket speakers in mine (97 LX450), I had no issues in the 5 years I ran that system with a factory head unit and amp. I hate to say that your problem was with the used amp, but that's what I am guessing.
- Thread starter
- #3
Thank you for the response. My only reasoning against the issue being the used amplifier is that I have replaced the original amplifier that came with the car now twice with two used OEM amplifiers from different sellers on ebay. Both of the OEM replacement amplifiers worked initially before blowing shortly after. The first used replacement worked with the blown OEM speakers and for a few hours after I replaced the speakers with aftermarket ones. The second one also blew somewhat quickly afterwards with me not even playing the radio at all. I am leaning towards suspecting the head unit but have no hard evidence to point to this being the issue.
SmokingRocks
hopelessly addicted to Cruisers
I would think voltage spikes and/or continuous overvoltage situations would be your only threat to the amplifier. Or you got unlucky and had two amplifiers that decided to give up at the same time.
Give us more details on the system, is it: 100% stock, stock but refurbished over time, or custom
Give us more details on the system, is it: 100% stock, stock but refurbished over time, or custom
SmokingRocks
hopelessly addicted to Cruisers
If you have an oscilloscope it would be very useful in this situation.
Agreed. You would think that consistent overvoltage or voltage spikes in the system (B+ voltage input) would show itself in other areas than just this one amplifier though...
- Thread starter
- #7
Car is 100% stock and was part of the reason why I purchased the vehicle. After I bought the car I replaced the Alternator with an OE denso one. I've been replacing other worn parts with OEM replacements. Only aftermarket parts are the four door speakers I replaced with alpine ones.
So. When you say that the amplifier "blows." What is happening? How are you failing the amplifier? Just no sound output? or what is not happening?
- Thread starter
- #9
The first time the amplifier blew I heard a popping sound while driving/playing music. The music stopped playing, antenna went down, and the radio was no longer able to be powered on. The second time I had not played the radio after replacing the amplifier for several weeks because I was planning on replacing the subwoofer and dash speakers but didn't end up doing this after checking the resistance at each speaker and noticing they were normal. When I attempted to power on the radio I was unsuccessful. I also checked resistance at the ground wire which was good.
This might not be your issue but when I bought mine it had an aftermarket radio and speakers and they would work most of the time. At times I would get an amplifier error and my radio would shut down. After troubleshooting for several days, by chance I was putting one of the speakers back into the door while the radio was on and noticed a small arc between the speaker and door. My speakers fit the stock opening but the frame was not as "narrow" as the stock one which placed the input terminals close to the metal frame. I solved my issue by purchasing two items (one for a fix and the other for better sound and reassurance that the speaker would not arc): 1) I placed a spacer on the door card which pulled the terminals just far enough that it was unlikely to happen; 2) purchased some silicone speaker baffles.
Hope this information helps.
Hope this information helps.
You checked the resistance of each set of wires to the speakers which is a good check to do, now check to see if you have continuity from each speaker wire to a good ground, you should not have continuity. If you find a grounded wire (continuity), then "de-pinning" the wires from the pack of the connector then plugging the connector back in may be a test to verify a grounded wire was the cause of the problem.
I had this issue a long time ago in a car I was restoring, I ended up running new speaker wires to both speakers on the rear package tray (again this was not a LC) and it fixed the weird electrical issue I was getting. Somewhere one of the wires was worn through and grounded out against the body, I was so frustrated I never found out where I just wanted it fixed. New speaker wires from the speakers all the way to the aftermarket head unit fixed the issue.
I had this issue a long time ago in a car I was restoring, I ended up running new speaker wires to both speakers on the rear package tray (again this was not a LC) and it fixed the weird electrical issue I was getting. Somewhere one of the wires was worn through and grounded out against the body, I was so frustrated I never found out where I just wanted it fixed. New speaker wires from the speakers all the way to the aftermarket head unit fixed the issue.
SmokingRocks
hopelessly addicted to Cruisers
Yea that is a solid test ^^
SmokingRocks
hopelessly addicted to Cruisers
Heres a couple pages from the FSM to help ya
- Thread starter
- #14
Hey guys thanks for all of the help. I was doing additional troubleshooting and resistance on all speakers was within proper specifications. There was also no continuity between any speakers and ground. However, there seems to be something strange going on with wires 3 and 4 on connector S4 (gray and yellow/blue wire) as in the diagram. Both wires have continuity to ground intermittently that is unrelated to connector movement. The gray wire shows constant .4V no matter if the 15A cig fuse is pulled or not. The 10A dome light also sees a constant 12V at pin 4 on the S4 connector regardless of if the dome fuse is pulled or not. Final note is when the dome fuse is pulled we lose continuity to ground on the gray wire but still have .4 volt draw even though this wire is not related to the dome fuse per diagram (it’s related to cig fuse). Thanks for all of your help. I’m really at a loss at what is going on.
- Thread starter
- #15
Also, is that FSM specific to the LX450? It was indicating that there was a subwoofer amplifier in the diagram which I’ve never heard of and wasn’t able to find anywhere. Does this part exist? I know the car has a subwoofer but does it also have a separate amplifier?
SmokingRocks
hopelessly addicted to Cruisers
ah shoot I missed the LX450 tag, the pages I gave you are for the 93-94. You'll need to download the 96 fsm to get your EWD, I doubt its much different but I know they made changes in the stereo
On the LX the 20 amp RADIO fuse powers the CD player and the Amp. The Amp powers the Radio.
The 15 amp CIG fuse provides ACC power to the CD Player and the Amp.
The 10 amp gauge fuse runs the cooling fan in the dash.
Disconnect the CD player to eliminate that part of the system.
I believe the LX450 has a relay in the left rear quarter panel for the left rear speaker. Its used to route that speaker to the optional cell phone. Maybe thats a sneak path for a short.
BTW, there is an unused 15amp 12 volt circuit in that quarter panel (protected by the TEL fuse) that could be useful for other accessories. You'll have to cut it out of the connector to use it.
Get the LX450 EWD. I cant imagine working on anything electrical without it!
The 15 amp CIG fuse provides ACC power to the CD Player and the Amp.
The 10 amp gauge fuse runs the cooling fan in the dash.
Disconnect the CD player to eliminate that part of the system.
I believe the LX450 has a relay in the left rear quarter panel for the left rear speaker. Its used to route that speaker to the optional cell phone. Maybe thats a sneak path for a short.
BTW, there is an unused 15amp 12 volt circuit in that quarter panel (protected by the TEL fuse) that could be useful for other accessories. You'll have to cut it out of the connector to use it.
Get the LX450 EWD. I cant imagine working on anything electrical without it!
