I have a 98 tdi discovery. It has been put into hi and low range when 4x4'ing, however the hi low range stick hadn't been put in diff lock for 6 plus years. It is very hard to engage the diff lock and no light appears on the dash when it is engaged. How do I tell if the diff lock is on or could the fuse or relay be stuffed.

 

I would suggest you try power washing the t/c linkage as best you can. Some will also crawl under and lube all linkage fittings. Worse case, without forcing the shifter and bending a linkage, you may have to pull the console and go thru the floor to the shift knuckle, clean and lube it.
In the future, shift it a few times a years so it won't freeze up.

 

Use a battery cable corrosion spray on the shift linkage to eat the corrosion.
Then lube it, work it lube it, etc. until it starts to move freely.
Once that is done the light should come on after a few times.
It is best to use it once a month to keep it working well, you dont need to move, just move the shifter into all of the gears.

 

Thanks Disco Mike.. I took the console out and accessed the hi/low linkage and used a spray which breaks down corrosion and also lubricates. Once it was moving more freely to the diff lock position the diff lock light came on on the dash for the first time ever. I sprayed the linkage quite a lot and it goes into D/L easy now but the light has stopped showing on the dash. Have I drowned the light contacts in there ???

 

Also thanks Spike 555, You were right when I was to get the linkage moving the light came on, but I think I lubed it too much with the spray and now the light doesn't come on. Even though the light doesn't come on, when the Hi/Low stick is pushed to diff lock it is engaged isn't it??

 

If the diff lock hasn't been used much the light can and does tend to stick either when coming on or going off. Just go wheeling now and enjoy the extra traction you now have.

 

I went for a quick drive on a close 4x4 track today and when I tried to get up a 2 foot soft edge on the dirt track to get around a fallen tree, even with the diff lock engaged and in low range, the back wheel would spin but the front on the same side would not. And the same on the other side.Any suggestions????

 

Be more specific, which tires were spinning and what do you have for tires?

 

With it in low range and diff lock on the right rear was turning but not the front right, and the front left was turning but not the back left. They should all turn shouldn't they? My tyres are a LT 225/75R16.

 

The front and rear differentials are open. The diff lock you can engage from the trnasfer case handle only locks the center differential in the transfer case, so the front and rear axles get equal power.