No headlights

Here is a weird one. My parents battery packed it in just as they were coming around to pick us up at 4.30 am to go to the airport for our Africa trip. So I used a booster pack to get them going so we could make it in time for our flight. It was lucky they own one and I was able to run to their place as it is only around the next block. So I told them to fit a new battery the same day after getting back from the airport which they did. But that night they went to drive but the headlights would not work. They checked the fuses and all were OK and Dad is a retired sparkie. The only way the headlights would come on is if they pulled back on the stork hold it like that. Funny thing is that a few days later they worked as normal again until we got back a few days ago 6 weeks later. Have not had a chance to look at it yet but seems strange that it happened after the new battery was fitted. It is a 95 XJ Limited the same as mine with the 4.0 so does anyone know what it might be?
If I cant find it quickly I might as well just build one of my headlight harness upgrades for it!

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They checked the fuses and all were OK
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The headlights by Fed law have a cheater breaker often built into the switch. A cheater breaker will reset itself after a short tripped time. But I don't think that's your problem anyway.

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The only way the headlights would come on is if they pulled back on the stork hold it like that
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Replace the switch

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. If I cant find it quickly I might as well just build one of my headlight harness upgrades for it!
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Most upgrades bypass the factory cheater/switch for main power to the lamps. Installing a fuse in the main power line to the lamps.
Now say your dad is going down a winding road at night. The headlights develop a short to ground. With the stock cheater the lamps go out for less then 5 SEC (in most cases) then come on again. The cheater will keep tripping and resetting. Hopefully giving you dad time and light to pull over without kissing a tree.
With a simple fuse. Once it blows he left in the dark.

Think it might be the switch then so will check it out tomorrow and order a new one from the dealer as no choice here!

Turned out to be the swtich so replaced that and made the high output headlight harness for it as well so it carrys no load. Took me just as long to change the switch as make and fit the whole new harness!