Fuses

[PlayingWithTBI]

it will erase all your learned fuel trims and stored codes (if any.) Depending on which fuses get replaced, you may be erasing that stuff anyway.

Yep, and if you look at the fuse box, there's a 30A fuse where a 10A s/b in the ECM slot. If OP wants to, he can check for codes before tackling this job. It looks to me like some PO had a box of 30AMP fuses and used them for everything.

 

[someotherguy]

Yep, and if you look at the fuse box, there's a 30A fuse where a 10A s/b in the ECM slot. If OP wants to, he can check for codes before tackling this job. It looks to me like some PO had a box of 30AMP fuses and used them for everything.

That one jumped out at me and concerns me the most.

The missing breaker is probably for an option OP's truck doesn't have, like power windows or seat, or something. I'd remember for sure years ago but it's been too long since I messed with 'em.

Richard

 

[DerekTheGreat]

That one jumped out at me and concerns me the most.

The missing breaker is probably for an option OP's truck doesn't have, like power windows or seat, or something. I'd remember for sure years ago but it's been too long since I messed with 'em.

Richard

Come to think of it, I think my truck was "missing" the same one too. I went to a treasure yard and put on in since I saw pins for it in the fuse block. Didn't notice anything working which didn't before. My truck does not have power windows or locks or mirrors.

So when removing the fuses should i disconnect the battery before doing so and also do you believe the fuses are a reason as to why my speedometer doesn't work even after switch the speed sensor and repairing the cluster?

Could be. Check for power battery voltage across the "Brake" fuse with the ignition in the "run" position. If I remember correctly, the speedometer gets power from that circuit. That ended up being the problem with my '88 C3500- the fuse terminal was all corroded.