2008 Sahara V8 Diesel Auto - corroded under dash wiring

[RaySimpson]

Hi all,
I just discovered this great forum while looking for answers to corroded under dash wiring on our 2008 Sahara.
This is our third pre-loved Croozer and its just right for towing our van around this wide brown land of ours. However we have discovered a big problem with the wiring harness under the dash, because the last owner failed to clean out the sun-roof drain holes and water has been running down inside the front pillars and all over the wiring harness, computer module and fuse box.
You can imagine the rest. The electrics are all buggered up: dash lights are a Christmas tree, won't engage/disengage Lo Ratio, etc, etc.
We are told it will mean a complete new wiring loom and computer module, with a repair quote in a range from $5,000 to $10,000 - depending on what they find!
Has anybody experienced this problem before, and if so, what was your solution?
I'm located in Sydney Australia.

 

[StarCruiser]

Hi Ray and Welcome.

Really sorry to hear you have this problem. Firstly I would go back to whoever sold you this truck and ask for it to be sorted if that’s possible. If you’re on your own I would assess it yourself. Repair shops are often only parts swap guys but they do have to do the job do that it’s reliable and not spend too much time doing it. Their solution will sort the problem but I doubt the whole loom is affected. Connectors will be the worst as will any electronic modules. You can try cleaning them up if you can get to them. It’s going to be labour intensive but if your saving $5-10k it’s going to feel easier. You can even try cleaning the modules. If you can open them up and have nothing to lose, try cleaning with a toothbrush and some soapy water (with them out the vehicle of course) but look for any sign that looks like a triangle with a hand in it struck through as this means they are static sensitive and will require you to be earthed or you could fry them.

Post up some pics.

Obviously before you do this you need to fix your leaks. Unless you’re certain about the sunroof drains I would be looking to see if the windscreen had been changed. It’s probably bonded in on yours and should be well sealed but could I suppose be leaking and looking like the drains. If it is the drains, check they aren’t holed or pushed apart from their connectors. Rarely do they really get blocked. Find where they come out under the truck and check you have flow. You could get someone to put a finger over the end and blow into them with another piece of hose to check for leaks.

No guarantees of success but if you remove corrosion and more importantly any conductive residue or even damp then these things can well be salvageable with time and effort. Electrical switch/contact cleaner is useful. Caig Deoxit is very good. Modules can be dried out by placing in a warm place such as an airing cupboard. Go fairly gently but electronics items are usually quite robust. Look for any broken tracks and repair as necessary. You’ll probably find very little damage and most of your problems caused by water sitting in the connectors which can be blown out with an air line.

Good luck with it.
Rich

 

[flint]

This might come in handy: https://www.toyota-tech.eu/wire_harness_rm/RM06H0E.pdf

 

[StarCruiser]

That does look useful Flint, good post!