Electrical system is dead

Truly, one of the most important tools to carry with you.

Pete’s car being a 1971, the head lights do not go through the ignition switch. As to most other older cars, I have not counted but every older car I can think of does not go through the ignition switch, which is why one can leave the headlights on and kill the battery.
Tom

2 Likes

Thankyou for the correction

My dumb :grimacing:

(Thinking off another vehicle that burns out ignition switches due to aged fan motors)

Pete,

You are probably running into a “feature” of the lates Series 2 wiring harness that has been discussed here before - yes, every single issue concerning the E-Type has been discussed here before; the challenge is finding the thread, as thread drift is very common… Sometime during the Series 2 production run the wiring to the fuel pump was changed. It used to come from the UNFUSED (white wire) side of Fuse #6. Later, a connector was added under the dash by the right hand A-post. As I understand it, the power from the ignition switch feeds into this in-line connector, and from there seperate white wires feed (a) the Fuse panel, and (b) the Fuel Pump. If you have power at the Fuse Panel on the white wire(s), but no power at the Fueld Pump, I would look for this in-line connector and try to locate the fault at that connector, or between it and the pump itself. The early part of this thread describes this: Fuel Pump wiring very late series 2

-David

David,
You got my hopes up but no cigar. I looked behind the glove box and found a sheathe with two right colored wires in it but one of them ended in an empty taped up solderless terminal. I’m guessing whoever rebuilt the car during restoration did something else for the fuel pump. At this point, I’ve decided to follow the wires forward toward the front of the car and see where they end up. Unfortunately I’m tearing up the interior to do so. It appeared to me that the two wires in the sheathe went from the passenger side to the drivers side behind the fuse panel but I lost it there. Anybody know?

David, I wonder if this wiring behind the dash was done from the first S1? On my 1967 1.25, the fuel pump wiring comes off the unfused side of the #6 fuse and goes behind the glove box. There is a connector there and from that connector the wire then goes back to the fuel pump. Also at this same connector behind the glove box, another wire leaves and goes to the ignition warning light. This is “somewhat” documented on the wiring diagrams.

4.2.2.pdf (122.4 KB)
This diagram is late series 1, but my earlier Haines manual series 1 diagram shows exactly the same wiring in this area starting with S/N 1E75001 OTS.

At #1, I circled the connector on the diagram that is behind the glove box. That seems to be very accurate. However, look at the wires at connector #2, one goes to the ignition warning light, the other side goes to the unfused side of fuse #6. On my 1967, the wire #3 between connector #2 and fuse #6 does not exist. Instead, the wire from the ignition warning light that goes to connector #2 actually goes to connector #1 behind the glove box. So connector #1 and connector #2 are actually the SAME connector.
At least that is what I have found.
Tom

I don’t think the wiring I described was done on the Series 1s, or even the early Series 2s. As far as I know, for all those cars the main white wire from the Ignition Switch goes directly to Fuse#6 from where switched power is distributed via unfused wires (White) and fused wires (Green - from fuses#6 and #7). Your description seems consistent with that - the inline connector#1 (and #2) are downstream of the unfused side of Fuse#6. The wiring topology that I described, which appears to be similar to that of the Series 3 cars, sources power for the Fuel Pump (and at least in the case of the S3, the Ignition and some of the warning lamps) directly from the Ignition Switch, and has a separate feed to Fuse#6. So, if you are searching for the white wire that powers the Fuel Pump, you won’t find it by systematically removing white wires from the unfused side of fuse#6.

1 Like

David, I believe I follow what you are saying- the change from the white wires from the fuse panel to the ignition switch. I was addressing the issue of the connector behind the glove box. It sounded like you were saying the connector behind the fuse box was added in later S2 production, I was saying it was much earlier, such as on my S1. I was not really addressing the fuse/ignition wiring.
Tom

I am normally the first guy to emphasize studying the circuit diagram and wire colors

However, I recently experienced ( similar situation to the PO…crank, no start)

Not a Jag, a much more complex vehicle, and the FSM called out wiring colors that do not match mine

So back to basics, but with a trick;

Use my trusty 12V lithium jump starter as a power source, disconnect main battery

I have made up a few test connectors that are a hatpin or paper clip soldered to wire with an alligator clip on each end…backprobes

The short story is I can stimulate and back test any circuit in the car with this and a test light

As a for instance, for the OP situation, and what I did

If no 12V present at FP final termination > fully disconnect battery > stimulate the fuel pump with 12V source and jumper leads > does FP operate, if not, take yr test light and apply to various points head forward on the harness where you expect your injected 12V should be.

I find it very useful to physically write a diagnostic tree

sorry if this sounds confusing. It can be hard to tell how much electrical knowledge guys have, my methods can be slightly unconventional, but I have years of experience fault finding as a field technician

You can bet that when you were in the field with a complex piece of equipment with which you were not 100% familiar that you wanted the FSM to have really good diagnostic trees, which they usually did, prepared by Japanese engineers

In my case, it was a failed fuel pump, caused by ingress of water, due to a poorly sealed o-ring, also disabled the fuel level sender. All fixed now

Out of frustration, I have routed a new 12v wire to the fuel pump and everything is working fine (so far). I’d like to thank everyone for their input.