If these wires had the braided (lacquer) outer insulation… that can turn to dust through the years leaving you with just the inner black insulation.
Sometimes the loss is limited to the exposed end and the same wire still has its cloth covering back inside the wrapped loom. Even then the colours may be hard to discern.
I’m going through a full continuity testing of all the wires running off the two relays that are present. The alternator checks out fine but there is a second wire off the c1 connector which I can’t identify. It doesn’t appear on any of the schematic drawing I have for a S2. Is it possible that a second component is running through this relay as well as the alternator? Also, I don’t appear to have as many relays as the schematic shows. The AC relay may have been removed when I took out the under the bonnet components related to it. Currently identified, alternator, mystery unit (assuming horn) directly under it, 2.coolant fans relays under the picture frame and the starter relay mounted by the windscreen washer unit. Puzzled is an understatement.
The C1 terminal on the alternator relay has two wires connected. One is colored NP and it runs to the F+ terminal on the alternator. The other, colored NR, is connected to the + terminal of the voltage regulator. It’s got nothing to do with the AC.
On the fan relay, there are two wires on the C1 terminal. If you had AC, you would have had a second fan relay. The second wire on the C1 terminal and a second wire on the C2 terminal from the first fan relay would have been connected to their mates on the second fan relay.
The horn relay only has one wire on the C1 connection.
The first wire on C1 terminated at the terminal post. Continuity there. On the second C1 wire I’ve got big resistance (nearly 2500 ) to the + terminal on the VR, but continuity on the VR’s negative terminal. The two wires running from the C2 pin sound like the two you are describing. The relay has two wires to C2 and two wires to the C1 pin, which is a 2 bladed common connector.
Also, do you know how many pins are on the horn relay? Schematic shows four but the relay I believe is the horn only has three. There is a spot for a c2 pin but nothing there. No loose hanging wire in search of a home either.
Ya that’s it the white one the black boot is not the problem. just disconnect the wires and hook them up one at a time or trace them separate
One goes to the ignition
One to starter
One I believe is for horns
I only have three
Cheers. Jim
It won’t matter if all wires that were supposed to be on C1 are on C2, and all wires that are supposed to be on C2 are on C1. However, what you describe sounds like you have a wire on C1 which goes to the +12v terminal post, and a second wire which has continuity to the VR’s negative terminal which should be grounded. So, you appear to have connected +12v to ground. If I were you, I’d be methodically mapping out what is connected to what on the car and comparing it to the circuit diagram. Then try to understand what might explain the differences (eg C1 wires switched with C2 wires by mistake) before moving anything. If you have 2 wires on C1 and 2 wires on C2 of the alternator relay, you have one more wire than you should, so that needs to be explained.
With regards to the horn relay, it sounds like someone may have substituted a 3 terminal relay (in which the C2 connection is made internally to the W1) for the correct 4 terminal relay. Though this may be functional, it will not work as designed, as Jaguar intended the power to the relay (on W1) to be switched by the ignition (G wire), and the power for the horn (on C2) to be unswitched (NP wire). If a 3 terminal relay is substituted, the high current to the horn circuit will pass through the ignition switch, which is not a good idea.
Damn Previous Owners…
“Negative Earth” could be your band name.
I’d like to make two points:
1/
Relays with no W2 terminal use the C2 terminal as their W2 connection, so it is not always possible to say this.
A short will be made if you get this wrong and the relay is operated. Check your horn and aircon relays if those are relays without a W2 connection and you have played with the wiring connections.
2/ From a safety perspective, the insulated bus bolt on the chassis should have ts wires arranged so that the starter motor cable is NOT on the opposite side to the battery cable. If you do that, 100 amps passes all of the way along the bolt and through the insulation. It’ll heat up and if one day it melts, it’ll make for a real mess. I’d measure what the theoretical current draws of all of the loom connections are on that bolt and arrange them so the highest current draws are nearest the battery eyelet. The biggest will be the starter motor cable by a long shot.
kind regards
Marek
“ I’d measure what the theoretical current draws of all of the loom connections are on that bolt and arrange them so the highest current draws are nearest the battery eyelet. The biggest will be the starter motor cable by a long shot.”
Great advice. Thanks!
Agreed. But if you read my comment you will see that I was talking about the Alternator Relay which I have assumed has 4 terminals, as (unlike the horn relay), they did not indicate that it had anything other than the regular 4 terminals.
While the alternator relay has only 4 called pins, W1 which have continuity to fuse #6, W2 continuity to body ground, C2 which has wire NP with continuity to the F+ terminal on the alternator and a second wire NP to VR+. All of that is in line with the wiring schematics I have from several sources.
And then I found that relay pin C1 does not.
Pin C1 on my alternator relay is a U shaped pin that would offer the opportunity to connect two single wires with female connectors wires similar to what occurs on C2 with the two wire into one female connector. That option apparently has been taken by someone, possibly me. The correct C1 connection with one of the wires is NR to the terminal post and has continuity.
The other is NW and according to the schematic should have been connected to C3 of the AIR CONDITIONER RELAY.which is no longer in the car.
How it came to be connected to the alternator relay I can’t explain. It has been removed but the short remains.
Is it possible that something in the alternator relay has fused or internally shorted when I attempted to hook up the battery? Am I looking for the short in the wrong place?
A C1/C2/C3 relay is a changeover relay. If the W1/W2 is unpowered, C2 will be connected to C3. When The relay is powered, i.e. there is 12v across W1 and W2, then C2 drops its connection to C3 and instead connects C2 to C1. This is probably at the root of your problem - a permanent short to ground.
If you think the relay is faulty, simply remove it from the car and test it with a meter separately.
The fan connection on a s3 car (and check earlier cars if aircon was an option) used such a changeover relay to control the fans. It was wired such that one side of the fan was grounded and the other side of the fan received 12v through the changeover relay via C2. When powered,up, the relay provided 12v to the fan through its C1 terminal (which then powered the fan through C2) and when turned off, it grounded the fan as C3 was earthed (so C2 went to earth). This meant both sides of the fan were grounded when the fan was turned off. (This was to stop the fan from backfeeding 12v to the ignition when the car was turned off, so the engne didn’t run on after you’d stopped the car.)
Obviously, you mustn’t swap a 6RA relay with one pinout type for another with a different pinout type without checking the consequences.
kind regards
Marek
On the Series 2 wiring diagram (NOTE: this is different to the Series 3 that Marek described), the NW wire is shown as going to C3 of a relay which has no C1 connection - this is the A/C blower relay, not the one that controls the radiator fans. The other end of that NW wire goes to the B terminal of the alternator, which also has an always hot N wire. As I believe has been discussed her before, that wiring diagram is in error - that C3 terminal should be labelled C1. It controls power to the A/C blower which should only be on when the ignition is ON (not, as would be the case if the terminal was C3, only when the ignition is OFF). It would be relevant to find out where the other end of that NW wire is connected now - if it is grounded, it would account for your problem. If, as you indicate, removing the NW wire from the alternator relay still leaves you with a short, then as Marek says, it’s time to systematically remove the wires from the alternator relay and determine if it is at fault. Before we go any further, please let us know how you are determining that the “short” still exists - I presume that you are not reconnecting the battery and looking for sparks 
I ask, as if you are using an ohmeter, to measure resistance between the battery cables, there could be quite a low resistance there anyway due to items that are always powered - eg the map light, if a door is open.
Resistance through the battery cables is currently 4.5, which honestly I don’t know if that is good or bad. Also, the wiring for the cooling fans is in order running through both relays even though the a/c unit has been removed. I suppose I could remove relay #1 and wire it directly to relay #2 but it is working as wired so I’m going to leave it alone.
Your comment about the map light prompted me to take another look behind the drop down panel and I found several questionable things. The map light you mentioned was poorly connected ( the dash was removed to recover.) easy fix. And then I found these taped wires off and I can’t find them on the wiring diagram.
#1 appears to be red/yellow. I can’t find a R/Y anywhere on the wiring schematic. It pigtails off the wiring loom running through the lower left side of the fuse/switch/gauge area. The very short length, maybe 4”, would put its male partner very close in the same area one would think. It is possible that this is a discolored R/W, but it sure looks yellow to me. There is a short R/W run that the schematic show going to “Instrument link” but I have no idea what that is.
#2 This Red/Black wire appears that it should be connected to Fuse #5 on the connected end. It disappears below the bottom of the fuse/switch/gauge area and seems to reappear from the same spot. The wire that reappears is loose and taped off. The only R/B wire I can find on the wiring schematic runs directly from fuse 5 to the #3 pin on the headlight switch. It is in place as it should be and has continuity. The taped off wire does not.
I appreciate the time you’ve taken to help me sort this out. As I’m sure is evident, automotive electronics is my albatross.
The Red/Yellow wire is for optional Fog Lights. The Red/Black wire is to bypass Fuse #5 for the tail lights for the German market. Your car is correct to have both of them disconnected (and hopefully taped to prevent them touching anything live).
4.5 ohms between the battery cables isn’t a dead short, but it’s still lower than I would expect with the ignition turned off and no circuits turned on. It would equate to a current of 3 amps flowing. To narrow things down you could disconnect wires one by one from the post connected to the battery + and see at what point the low resistance goes away.
Thanks! Just the type of instructions I needed!
