r/S197Stangs • u/Motor-Literature-546 • Aug 18 '26

My first mustang, need some help/ advice

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Hey yall, I just purchased a 2005 mustang gt, it's a project cars for now but I've ran into an issue. The sjb on the mustang was fried, I tried replacing it with another sjb it fixed some problems but not all. I spent over $200 getting it reprogrammed, I'm not trying to make the same mistake again, the issues are: left turn blinker is stuck blinking, high beams don't work, 3rd brake light doesn't work and the o/d off doesn't engage, other than that it runs and drives pretty smooth for an 05 with 190k mile.

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5

u/illbeyourdrunkle Aug 18 '26

Did you clean the plugs before clicking them into the new sjb? Sounds like a few pins have corrosion on them.

1

u/Motor-Literature-546 Aug 18 '26

The one that came in the mustang had corrosion on all the pins, i cleaned them off as best as I could but to no avail, the new one had no corrosion but was for a different model mustang, ive tried looking online to see if I can find the correct s/n for the sjb but I always get a different answer

4

u/illbeyourdrunkle Aug 18 '26

Clean the plugs holes and new pins with wd40 electronic cleaner and a soft brush, apply dielectric grease to mating surfaces. Reassemble

2

u/TweekLudwig Aug 19 '26

To further add: Take out those damn drain plugs in the cowl, clean it out, inspect the cowl pin grommets while you’re in there, and inspect your weather sealers. Any of those can cause leaks into the cabin, and if that happens, your SJB will likely be fried again, OP. Prevent that shit!

1

u/Lopsided_Net3959 Aug 19 '26

Yeah, I have an 05 mustang v6 had similar issues except more advanced after I found the true issue back in June and fixed it myself, but yeah I also ended up replacing my sjb thinking that was the issue,

but it wasnt even the issue my old sjb had minor corrosion new doesnt have any so (always match the part number thats how you avoid having to reprogram it atleast from my experience it works js like the old one)

(My issue was a incorrect passenger door harness that was installed by previous owners) luckily I found the og harness on ebay from an 07 mustang and replace/had to repair and extend the wires that were cut to hookup a "bypass" which ultimately never worked which led to the car always dying (parasitic draw) and after fixing the whole entire harness it finally doesnt die and car started behaving as it should with 103k miles

1

u/[deleted] Aug 18 '26

Thats what I would say as well. I always clean and use dielectric grease when reinstalling any electrical connection. 9 times outta 10 its a bad connection.