Few 300TDi questions

Hi all,

First off my heater doesn't work, just blows cold air, well it blows hot for about a second. no leaks inside so I don't think the matrix is fubared, I was told by the last owner that it may be a blockage in the water feed pipes, ive taken them off and a bit of water trickles out, but Im not sure how much water should come out

Second question, Im wiring up 4 55W spots on a roof bar, I have factory fitted spots on the front bumper and wish to 'piggy-back' them off these as I wish for all the lights to operate off one switch, is this safe to do so? If so what amperage cable will I need between the new spots and the old? and I guess I will need a in-line fuse?

Many thanks to all
cheers Callum

Check thermostat & replace first they cost around £5

As far as the heater goes, mine blocked up too but water still went through it. Gave me a false idea of it working so I reckon there is a bypass run off the main feed. Your 1 second blast is probably heat transfer down the standing water. Watch out for overheating of the radiator if you push the engine too, I had to bypass the heater to prevent this happening, something to do with the flow I was told. The main problem is having to take out the dash to replace the heater!

For your lights and piggy-backing, I would suggest you use the factory fitted spot live feed to operate a relay. Run a separate feed to the new lights switched by the relay.

Many thanks Skynet, if it involves removing the dash I think I will put up with the 12V fag lighter heater and being cold haha, In regards to the lights I think I will do that, unless anyone says that direct piggy-backing is safe
cheers Callum

For the roof lights to work in conjunction with the existing spots you need to take a feed direct off battery +ve thro a fuse and thro a relay.
Switch the relay by taking a feed off the wiring that serves the existing spots.
Or if you can switch the new relay by taking a feed off the circuit that switches the existing relay feeding the existing spots.
Hope that makes sense, it does to me

Callum you would be looking at pulling an extra 11A at least with 4x55W lights, not ideal to piggy back on the fitted wiring. Separate fused feed would be my choice.

Skynet said:

Callum you would be looking at pulling an extra 11A at least with 4x55W lights, not ideal to piggy back on the fitted wiring. Separate fused feed would be my choice.

Click to expand...

think yu need to redo yo maths, Sky...........

4*55 = 220watts.
220/12 = 18.5Amps

The Mad Hat Man said:

think yu need to redo yo maths, Sky...........

4*55 = 220watts.
220/12 = 18.5Amps

Click to expand...

watts/power/Ohms law should we discuss adiabatic equation and circuit grouping

I hate to think wot pics yu have of "circuit groupies"

sorry to butt in here, but my question doesn't seem important enough to start a whole new thread...

there is a factory-fitted feed meant for spotlights even though spotlights were factory fitted???

i'm about to re-wire mine (with the help of an car-electrics expert/friend who knows nothing about Landies in particular). Other than trying to understand the wiring diagram in my haynes manual, are there any clues as to where this feed is?

well I did say at least .... /goes back to pencil and paper

The Mad Hat Man said:

think yu need to redo yo maths, Sky...........

4*55 = 220watts.
220/12 = 18.5Amps

Click to expand...

so the fuse would need to be 20 amp on 20 amp wire?

20Amp fuse on 30Amp wire.

Thank you all OK my mind is made up on the lights I will do what everyone says, what sorta relay is it?

30amp 4way

4 Pin Relay set of 2 on / off 30A 12V on eBay (end time 15-Jan-11 10:41:54 GMT)

Im guessing the 4 pin is pos and neg of the OEM wiring and pos and neg of the new lights?

Nope, relays have a battery in, new lights out, old lights in and earth.

I can't remember which numbers is which.

I don't want to disagree for the sake of it, but I think that 30 amp wire is excessive, I'd say 25 would be ok.

I just wired up 6x55 watt on the roof, and I ran 2x 16.5amp twin core up there, each twin core serves 3 lamps each.

Either way your auto electrician should know how to wore up some spot lights! I would consider re wiring the whole lot to make a nice neat system, 1 relay for roof lights, 1 for front lights, both fed from battery with an inline fuse each, both switched from high beam, etc etc.

Saves you piggybacking here there and everywhere and ending up with a messy system that's hard to understand when it goes wrong!!

Cheers

Can't make my mind up what I'm going to fit.
I've removed the valance and factory fitted spots off my 98 300tdi (increasing front clearance).
Obviously still have the wiring (taped up) along with a ready wired switch, but stuck between light bar above screen or a couple of spots on the bumper.
Would like to avoid too many changes to the wiring as I'm not confident with electrics.

The roof lights are great for off road because you can angle them outwards for great all round vision. They are not very good for driving at speed though because they illuminate the bonnet and dash, and this spoils your concentration. I fitted mine for laning and they are great, but I leave them off for road driving.

Front spots are the opposite, much better on road, still good off road bit not as handy as having the light further back, near the drivers viewpoint.

Cheers.

Ideally you want your roof spot on a separate switch to the rest of your lights, that way you can turn your lights off if you go wading and still be able to see where you are going.