Starter relay issue

Hello I wonder if someone’s could help me, I believe I have a issue where the white/red stripe wire from the starter relay is showing as earth. I have disconnected it from anywhere motor side and I’m still getting continuity on ground. Any ideas what could be causing this or where is should start?

Car is a XJC 1977


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First, that isn’t the starter relay…so you might be going down a bit of a garden path!

The starter relay should is metal, approximately rectangular, and has alpha-numeric terminal designations such a W1, W4, C1, C2, etc

It’s mounted on the firewall on Series III cars…not sure about Series II.


Looks like your relay has been replaced.
Here is the original type, located on the scuttle near the center, just below the center braces.

But the function of one marked 30 85 86 87 should be the same.
In the wiring diagram white/red goes to a cold start relay and an output unit, so it probably means you are not really disconnected yet.
Better get a Heynes manual and figure out if your car has been bodged up by a low budget repair.


I have a friend with a late model Series II XJ6 and the starter relay
appears as you state and it is located on the firewall. The red Lucas
relays shown in the picture are used on my Series III saloons for rhetoric
auxiliary cooling fans.


Since the picture doesn’t show the starter relay, Aaron - what are the symptoms leading to suspecting a starter relay problem…or any relay…?

A genuine starter ealy problem should show up as a cranking problem…so…?

xj6 85 Sov Europe (UK/NZ)

WThanks gents no doubt I’m down the garden path, I’m trying to figure out why the white/red stripe is wired to the live of a fuel pump, if I can find out what the line should be giving I can work out if it’s something which is earthing somewhere or if I can just remove altogether. If it’s a auxiliary fan I suppose I can remove the wire to the pump and just see what stops working. I have a wiring diagram on the way.

All ideas are appreciated


First step is of course to identify the item shown, Aaron - and a wiring diagram, showing relevant wire colours, will do that. What are the other colours…?

White/red is usually associated with the starter solenoid - and appears grounded through the solenoid if ohmed. (Ohming connected circuits tends toward a ground reading). If the item shown seems associated with the fuel pump - it may be the fuel safety relay. Which reacts to cranking but otherwise stops the fuel pumps if the engine is not running…

xj6 85 Sov Europe (UK/NZ)

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Hello Frank thanks for the reply yes I have a wiring diagram on the way but that’s great info about the ohms output I will test that, it makes more sense to me now.

Also it’s a fuel diode pack not a starter relay as I initially thought it only fitted to late series 2 early series 3 cars.


The diagram on the unit itself tell us it is a relay, not a diode pack.

FWIW, on Series III 6-cylinder cars that style and color of relay, using that type of bracket, was for the electric cooling fan, as mentioned. The wire colors were various combinations of green. Mounted to the left of the radiator.

When you get your Series II diagrams the mystery should be solved.


Doug, Aaron,

The red Lucas cooling fan relay in the Series III XJ6/12 is Jaguar part number DAC1028, Lucas part number SRB411 and also Lucas part numbers 33374, 33374A and 33374B ( and possibly others).   When I looked this part up in my Series III XJ6 Part Catalogue (RTC9897CB of December 1995)  I saw on page 2E06L that the 3.4L cars also used the DAC1028 as a “Fuel Cutoff Relay” on the page titled “Starter and Fuel Cut-Off Relays”.   I thought that was interesting (I don’t now anything about the 3.4L cars). Then when I looked this up in my copy of the Series 2 XJ6 Parts Catalogue (RTC9097C of January 1977) I discovered that DAC1028 (Jaguar part number C31791 in this document) shows up on the “Starter and Fuel Cut-Off Relays” page on a bracket on the firewall right next to the Starter Relay (Jaguar part number C36611).    So I believe the red relay is correct in Aaron’s car as the “Fuel Cut-Off Relay” and it should be sitting right next to his Starter Relay.   I am confident that is what he will find out when he gets the wiring diagrams.   I find that having a comprehensive library of Jaguar Parts Catalogues, Service Manuals, Owner’s Manuals and other official Jaguar publications enables me to sort out many mysteries not only on my cars but also for others.  They are worth their weight in gold and I am certain that I have saved the cost of the documents many times over by being able to shop around for parts by the correct part numbers and being able to trouble shoot down to the failed component before buying parts.  


Paul M. Novak

1990 Series III V12 Vanden Plas

1990 XJ-S Classic Collection convertible

1987 XJ6 Vanden Plas

1984 XJ6 Vanden Plas

1969 E-Type FHC

1957 MK VIII Saloon

Ramona, CA USA

Good research, Paul !


what problem does your car display?..starter fail to turn, relay clicks only, (or not), fuse blown etc

One way or another, Aaron - all connected connections wind up to ground. Through devious ways, certainly - usually showing some resistance unlike a plain ground…

As Doug remarks; the item shown is not a diode pack, but a two-way relay. I suspect a fuel safety relay; the red/white powering the fuel pumps while cranking. A oil pressure switch engage the pumps when the engine is running - basically preventing the pumps from running with the engine stalled. A safety feature with carbs - solved differently on EFI…

However, it may of course be something different - but in any case; a PO may have bastardised/bypassed whatever it is, rendering testing inconclusive…

xj6 85 Sov Europe (UK/NZ)

here’s a diagram of the charging and ignition circuit

Wire Colors
N = Brown
B = Black
W = White
WU = White & Blue
WR = White & Red
WY = White & Yellow
NB = Brown & Black
WK = White & Pink

I ran into this same issue last summer. I ended up replacing the relay. Oh, and I un-pinched (it’s a word that I just made up) the corners of the relay so I could see inside so I could figure out what wire went where.

Hope this helps

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Ha, ha. I will confess to, in my starving college student days, having unpinched a couple of relays to take them apart and clean the contacts because I was too poor/cheap to buy new relays.


Hi very good morning from Ireland im David it’s a pleasure… about starter relay best option is go 14DCV80amp better job much better quality I can show you a few pictures how to wiring up …

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