2001 XJR, previous owner had a shop replace the factory head unit with after market, and also had an aftermarket amp spliced into the wiring in the trunk. He tossed the factory head unit into the trash, but left the Alpine amp in the trunk. I have acquired a replacement head unit, and it's on its way to me, so I thought I would tackle undoing the wiring mess in the trunk. Luckily the shop left the connector in the Alpine amp, and snipped wires off leaving me an inch or two to splice back onto.

First step is color matching all the wires on one of the Alpine connectors. Most of it is easy to figure out, but Jaguar loves to use the same wire colors even in the same connector.

In these two pairings of pins, I have a yellow and a yellow/red stripe

PIN Pairings:

• 8 & 18
• 6 & 16

I think based on my reading of the wiring diagrams, that these are the front right tweeter and the front left tweeter. But which is which? I can't find the pin out for that connector




Thanks in advance! I know I will have more questions, this is just the first connector I have tackled, I know there are more. I dread seeing what's behind the head unit, but I'll cross that bridge when I come to it.


Thanks!

 

You'll have to do some metering, the A pillar cover comes off rather easily, you just have to work it off slowly. Jag just kinda seems to have thrown the tweeters in on the schematic. When they go into the factory amp, your guess is as good as mine as to how they interfaced it. It's one of the reasons I dumped it and re-pulled my own wiring to the head but used the out to the speakers. I didn't use the tweeters...as a matter of fact, I'm dumping my garbage Clarion in the very near future.

 

2001 has different wire colours than what is shown in the 1998 diagram. The two pairs, yellow & yellow/red, are for the Right A-Post Twitter and Front Door Mid-Bass. You can touch a small 1.5 volt battery with each wire pair and listen for faint crackling coming from the mentioned speakers.

 

I attach the full radio diagram for your tracing of other connectors.

 

Got it, so I'm part of the way there. I know which pair of yellow and yellow/red wires goes to the tweeter, and which pair goes to mid bass in door. Can anyone help me on the other part of the connection? In the stub of the amp harness I have pictured above, which pair goes to tweet, and which one goes to mid bass? I can't find a pinout or diagram of that connector. I'll edit my question on the pic here.

 

I have always sucked at deciphering wiring diagrams, but I finally took the time to learn what I was looking at, and what all the bits of information are. From the diagram that folks, including M.Stojanovic provided above, I finally figured out that the designation IC-31 in the working diagram was the connector that handles all of the outgoing signal to the speakers from the Alpine amp. The I deduced that the second part of the IC31 designations was the pin number printed on the connector itself. As in IC-31-8 is pin number 8 in that connector.

That means (if anyone sees an error here, let me know. TY)

• 8 & 18 - is the right front tweeter
• 6 & 16 - is the right front mid bass

I actually think I have all of the connections planned out now. I have removed the Kenwood amp from the trunk, and prepared the wires to be respliced back there to reconnect the Alpine amp. I have a replacement OEM head unit on the way to me that has been modified with a bluetooth function built in for both music streaming and phone calls, and I have resorted the wiring in the dash for that to plug in with hopefully no drama.

I know the Kenwood head unit and 4 channel amp the PO had installed was likely somewhat better quality than going back to all OEM, but I mainly listen to Sirius XM streaming through the app, so I'm not getting audiophile quality no matter what. I really hated the look of a modern flashy head unit in the waterfall console. Just ruined the look for me.

Left to do:

• install head unit when the brown truck brings it
• work slowly through reconnecting wires in trunk (a few a day, otherwise my back kills me being bent over the trunk for too long)
• refoam rear deck subwoofer. I have the kit from speakerworks to repair the disintegrated foam

 

Okay, one more question. I have all of the wires on the speaker connector spliced, and I’m 97.4 percent confident in all of them!

Now for the other white plug that goes into the amplifier. It has 2 black wires coming to it, and two brown/red wires.

What the heck are these, why do I have two of each color? To be clear I have two black wires coming from the loom, and I have two brown/red wires coming from the loom. And on the plug, I have 2 black stubs, and two brown/red stubs.

Does it matter which black goes to which? Does it matter which brown/red goes to which?

the reuse of wire colors is so British!

 

How many pins does the connector you are talking about have? Is it maybe the connector IC30 which is shown on the diagram to have 12 pins (the highest number is IC30-12)?

 

I think it is the IC-30 connector. My challenge is the pair of black wires and the pair of brown/red wires all go into the wire loom and head off towards the front of the car, and I have no idea if it matters which is which. I think oth blacks are ground, and I think both brown/red are positives, but I’m not sure if one is switched or un switched.

When the Kenwood amp was installed, they had both black wires going to ground, and both brown/red wires going to positive.

 

The diagram shows that there are 4 black and 2 brown/red wires in IC-30. All 4 black go to ground and the two brown/red go to positive (permanent 12V) supply in which case it should not matter which connects to which as long as the colours are matched.

 

Perfect! I assumed that to be the case, but wanted confirmation. The brown/red wires must be an un-switched 12v+. During splicing I accidentally brushed one of them against the inside of the rear fender, and saw a brief spark. Now I'm not testing 12v+ with my meter. I assume there's a fuse I will need to place, but that should be easy.

Thanks for all your help on this, if we ever cross paths, I owe you a beer/whiskey/coffee/beverage of choice!

 

It is extremely nice to have such a wealth of knowledge and experience
when it comes to taking care of our cars.

 

Okay, I think all the wiring is figured out, but one issue remains. As I stated above, I did not realize any of the wiring was constant 12v+, and I know at one point I brushed one of the brown/red wires against the inside sheet metal and got a brief spark. Now I do not have 12v at those wires. I checked the fuse diagram, and found a 30 amp fuse marked audio amplifier in the fuse box beside the battery in the trunk. Test light does not show 12v on either side of that fuse, key off or key on. 30 amp fuse checks out good. There is also a 5 amp fuse in that same box for radio, but it tests fine as well. Where else should I be checking? What other fuse or component may I have tripped when that brown/red wire touched ground?

 

The brown/red wires get power from Fuse #12 in the trunk fuse box. This fuse is specific to the amplifier and it is always "hot" (as long as the battery is connected) so you don't need to switch the ignition "on" when checking power on it. The line from the fuse to the amplifier has an in-line connector somewhere so, perhaps, you can look for it and then check the continuity amp to connector and connector to Fuse #12. See the attached fuse box diagram.

 

I'm not getting power to fuse 12 at all. Which is what makes me think I’ve blown a fuse or relay somewhere upstream of that.

 

There is no fuse or relay upstream of Fuse #12. This fuse is connected to the "Battery Power Bus" as you can see on the diagram I attached earlier. This Power Bus provides (constant) battery power to Fuse #12 and also to nine other fuses. If you have power on the other fuses, it means that the link of your Fuse #12 to the Power Bus has blown (instead of the fuse blowing). If this is the case (all other related fuses have power), you will need to take the fuse box out and try to locate and repair the link to Fuse #12.

It is a general rule, and especially important in the case of Jaguar, that you disconnect the battery before doing any work on the wiring. Jaguar also advises that the battery is disconnected even when you are just unplugging and plugging back in any of the wiring connectors.

 

Yay, I have success! At least for now. I still don’t have a head unit, but I think all of the trunk wire spicing is complete. I found the issue with power to the amp and now all is reassembled. I also installed a used CD changer I purchased from a salvage yard on eBay and it powers up. Bonus: it had 6 CDs left in it from a previous owner, including 2 Led Zeppelin discs and 2 Queen discs! Also 2 discs of what sound like metal music, but in Spanish. Those two may not get as much play!

Thanks to everyone for all of your help, now I await my head unit to see if all this works!

 

For the benefit of other members who may experience similar problem, you should inform what the issue was.

 

Turned out to be super simple. One of the legs of the 30 amp fuse wasn't being gripped tightly by the slot in the fuse box. I tested for power at the top of the fuse and got nothing , but when I removed the fuse and tested for power on the connects, I had 12 V. I disconnected the battery again, used a tool to slightly alter the shape/tightness of the contacts, and all was good.

 

Bonus points for Zep and Queen!