Greetiings --

In brief, my wife (!) has a 2001 XJ**R** with the non-premium (I think) sound system with navigation but without a CD changer (there is a hole in the trunk liner for the changer but it is not present on this car). This system features an amplifier at the top of the CD/DVD drive stack in the trunk which is hidden behind the trunk trim.

The amplifier features a cooling fan. Either the fan alone or the fan and amplifier are intermittently “running” at various times (I can hear the fan — sometimes it runs with the key off, sometimes it doesn’t) and that is draining the battery (it takes a couple of days to do so, typically).

I posted an inquiry on another thread to see if anybody else has had this problem, to no avail. Thus, I need to divine my own solution.

While one solution is a battery tender, I really prefer fixes.

Thus I hope to either repair the amp (which I believe to be LNF4170AA) or the power head (which I believe to be LNF4100AA with navigation buttons and cassette) or, if I can’t do so, insert a crude logic circuit that positively switches the amp’s power supply, perhaps using antenna power as a trigger.

I have also bought on eBay an amp so I can root about inside it a bit.

Amongst other questions, I need to confirm the type of audio system I have and understand it works.

I have used my iCarsoft i930 Jaguar-specific scanner and have not been able to identify an audio module. After reviewing the “XJ Series Sedan 2001 Electrical Guide,” the absence of an audio module leads me to the conclusion that I have the non-premium audio system with navigation.

Can anybody confirm that?

Assuming that I do not have an audio module, I assume that means that power to the amp should be switched/sent **or** signaled by the audio head unit.

Can anybody confirm that and how the power “flows”?

I think that either (1) the head unit power or power signal to the amp is not being turned off, or (2) the power or power signal is being sent correctly by the head unit but the power relay inside the amp intermittently malfunctions, powering it intermittently.

In the alternative, it is possible that the amp itself is always powered so that the fan can run to cool down the unit but the amp itself is being properly switched. If that is the case, as was suggested in another thread, is is possible that the “heat sink sensor for the fan is faulty and causing your issue.”

I would appreciate any thoughts in that regard.

Finally, I think there may be some sort of optical cable in the mix which might complicate things.

Can anybody tell me what the optical cable does?

Sorry for all of these questions but this is new territory for me; I’m a bit of a technophobe who proudly wears a SMITHS (yes, that SMITHS) wind-up wristwatch so I need all of the help that I can get.

Thanks in advance,


— Kevin (’69 E-Type, ’01 XJR, ’01 S-Type, ’03 S-Type NAS 5-speed manual, lots of others in the past)

 

As I answered part of your question on the Jag Lover's forum.


motorcarman
11h

If you have an AMP in the boot, then you have PREMIUM SOUND!!!

bob

 

In answer to another of your questions, The power amp (Alpine Premium Sound) has battery power at all times on 2 wires (pins in connector IC 10-1 and IC 10-2) from LH heelboard fusebox #9 fuse (10amp).

Power 'ignition-on' to amp (pin in connector IC 10-7) is from fuse #3 (5 amp) in Trunk Fuse Box.

Very easy to remove the fuses and see if there is a current draw (ammeter) with the radio head unit OFF.

Figure 16.2 in the Electrical Guide shows the wire colors and all the connection I have described.

bob

 

Thanks, Bob – that was extremely helpful! I have pondered the Electrical Guide but I must confess that it has not “clicked” for me yet – I don’t have a technical background and I find “stuff” like that to be challenging.

Since the power amp has battery power at all times, I think that points me towards the “heat sink sensor for the fan [being] faulty and causing [my] issue.”

My eBay amp arrives tomorrow and I will study it so see if I can divine said sensor. I believe that they are typically diodes of the sort that used to be available at Radio Shack prior to the firm’s sad demise.

Thanks again!

– Kevin

 

it may just need a blast of compressed air?

 

Is this true for 2002 XJ8?

 

Gotta be careful as there was a head unit change in the X308 production and there may have been also one in the premium setup separate amplifier part number as well as how it is wired . I haven't looked at the difference .

 

00+ premium (Alpine) audio systems use the 8-way Alpine round connector for audio communications between the head unit and amplifier. The switching on/off of the amp is controlled by this connector! However, there is no pinout given in the 00 electrical guide for this connector, so not a quick way to determine which pin is the turn-on signal. If it is unplugged then the amp should be off (there will still be B+ power going to the amp, but it will not be receiving a signal to stay on).

I did manage to find the pinout diagram online. looks like pin 1 /may/ be the turn-on signal:



98/99 HK premium audio amps use the Multilock rectangular connectors, looking carefully at the pinouts page for diagram 16.2 on the 98/99 electrical guides it tells you which pin is for amp switching, and audio channels.


The takeaway from all this: unplug the round connector when the amp is running with the car off; if it is an internal amp issue like an overheat sensor it will continue to run, if it turns off it may be an issue in the harness or head unit, etc.

 

Brilliant! Thank you so very much! This was exactly the information I was hoping to receive from somebody who his prettier and smarter than I am (an admittedly low bar...).

I will disconnect/reconnect and post to the thread the results!

 

As luck would have it, my wife dropped by my office shortly after I posted my last message and I was able to test the amp right then and there.

When I plugged the amp back in, the fan did NOT run.

I left the amp plugged in and will check it from time to time and will take the diagnostic steps when I again hear it running.

Two more questions:

(1) In addition to the Ai-Net female jack on the amplifier, there is a cable with a male Ai-Net plug coming out of the amp. It is not plugged into anything. Is it the plug for the CD changer (which my wife's XJR does *not* have)?

(2) The Ai-Net cable plugged into the amplifier (it has gray, plastic shielding) would not unplug even after exerting an uncomfortable amount of force. Is there a trick or should I just pull until it lets loose?

One observation:

It was very cold when we bought the car and stayed cold for quite a while (it was also rainy as all get-out). When the battery drain/fan running problem emerged, it was quite a bit warmer (the high that day was 55ş). The current temperature is 42ş and the fan is not running. I think this problem is temperature-related but it will take more observations to confirm that suspicion.

 

The answer to 1 is yes. To 2 I don't know, may need to wiggle carefully, I don't think there's a locking ring to pull or anything, but my car doesn't have it so I don't know for sure. I think the CDC on the 98/99 cars also uses AiNet, but only for the CDC, and I don't remember any tricks needed there.

 

I am chasing a similar gremlin wanting to keep my amp fan running when the car is off, so this thread is very helpful!

Kevin, I found the Ai-Net cable very difficult to unplug from the amplifier. But it will come out with a good degree of force and wiggling it back and forth. When I finally got mine unplugged, the fan in the amplifier stopped and the power drain on the multimeter ceased.

nilanium, your diagram and comments were extremely helpful to my issue. With the round connector unplugged, fan no longer running and the power drain ceasing, your opinion is the amplifier is not the cause of the issue. Plugging in the round connector and it coming back on drawing power and the fan running, something is calling for the amplifier to be switched "on" even when the head unit is actually switched "off" and the ignition is not on. I was going to replace the amplifier, but after reading your post, is seems that will be a waste of money by not resolving the issue.

-Kent

 

Kevin,

I removed my head unit (losing one of the mounting screws into the nether regions of the center console) and unplugged the round amplifier connector. The amplifier fan went off. The amplifier fan running and battery drain started with my original head unit. This is a used one from eBay. The problem persists with the used head unit. I wonder if after time, these head units have a propensity to have a component failure that tells the amplifier to be on even when the head unit is switched off. I called Short Circuit Car Audio Repair in San Jose and he thought the amplifier might be the culprit. I asked why would the head unit be sending power to the amplifier if the head unit is switched off; shouldn't the signal to switch on/off the amplifier originate in the head unit? His reply was to send in both components and they would test them. I was hoping for a simple "yes, the head unit controls the on/off operation of the amplifier (or not)," but no such luck.