Engine will not turn over. silent when key turned. battery good. I have tried these things

Problem:

Engine will not turn over. Silent when key is turned. No ignition, no power to instrument panel, headlights or power seatbelts

Battery is new and working. Radio, fans, some exterior and interior lights working

I have tried starting car in Neutral, no good.

Seems to be a bad starter relay.

I touched the contacts on starter relay and the starter motor did wake up. I have a replacement ordered.

There is an ABS / ECU relay under the driver’s kick panel I have not touched.

I have checked these fuses and found them good:

Starter motor solenoid

Instrument pack

Ignition circuts

Several others I cannot recall exactly. All good.

Note: this may be irrelevant information but I had just put a can or 44K fuel system cleaner in the gas tank. Drove it for about 30 minutes. After I turned off car it would not restart. Could be a coincidence.

Welcome to the forums.
44k would be a red herring, you said when you shorted the starter relay the engine turned over? If thats the case then I would say thats the problem.

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Several iterations of XJ40.(please pick one)

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So I thought, but the new relay did not solve it. Perhaps it is not the correct relay, i purchased it at an Autozone type of place. I also wonder, why would a bad starter relay alone cause a loss in power to headlights, instrument panel, seatbelts… Could this be the ECU…

Dave, perhaps a failed ignition switch? I’d check and clean every ground point, remove both fuse boxes and check the solder joints, also inspect all the relay modules and their solder joints.

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I think you are correct. It’s on a tow truck on its way to the shop. I’ll post the results.
Thank you all.

This might be a case of ‘too little too late’ but does this sound familiar?

For what it’s worth this sounds exactly like what happened with the starter motor in my 1990 model 4L XJ40. When I’d turn the key to start everything electrical just went dead. It happened one or two times where after a little while I tried again and it started just like normal (and did so for the next few starts too). Then it started happening every time.

With the starter motor removed I tested it with a car battery and it spun up faultlessly every time, no matter how much I knocked it about trying to encourage a loose connection inside to reveal itself. Still I couldn’t think of anything else, so I replaced it with a starter motor pulled from my parts car and that’s been working without issue for years.

So either the starter motor or the starter solenoid can somehow fail such that it intermittently shorts out the electrical system (surprisingly without completely self-destructing), or makes a very good impression of doing that. Unfortunately replacing the starter is a real pain of a job due to a mischievously-positioned top mounting bolt.

The problem was a ground to the ingnition switch.

Dave, thanks for following up. This is how we all learn. Having this documented in the archives will help others.

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If you know, where was this defective ground located?

I don’t know, a mechanic did the work