Transmission light and limp mode after hard rain

Been working on this one for a while, finally making my way here. I have a 1991 XJ40. I’m already aware of rain getting into the car, but I forgot the cover one night and a big rain hit. The day after, transmission started acting up, but only after warming up for a bit.

Felt like Limp mode. Transmission light didn’t come on neither did error codes. The Transmission light eventually did come on after battery drained out / was charged again.

Checked the TPS and checked the purple cube relay under the hood (I believe that’s the transmission relay).

Water enters the gearbox computer through the wiring harness. Seal the gland under the vacuum accumulator under the battery. There was a jaguar service bulletin for that. Check if the gearbox computer inside is not wet.

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44-24.pdf (31.3 KB)

From reading up on tech bulletin 04-18, my 91 has the battery in the Boot (trunk) would be gearbox computer be located under the firewall?

Odd that a 91MY would have the battery in the trunk? I thought that was just 1993MY on?

…->92, the computer is located under the passenger compartment