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daveturnbull

Deleting dim dip from loom

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I'm currently in the process of sorting out a new loom for my hybrid. Starting point is a 200 tdi loom as that gives me blade fuses and the right connectors for all of the switch gear. 

I've been making a few changes to the loom, and was wondering what to do with the dim dip bits. I don't really want them, and I know you can disable by unplugging the resistor, but as I have the loom on the table I was considering just stripping it all out and getting rid of the relay too. 

Good idea / bad idea? DSC_1412.thumb.JPG.765abef359d21feb9dde6bb35293e054.JPG

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Remove the Pink case dim dip unit & in the base socket join the 2 blue/red trace wires together. 

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Thanks Ralph. I've spent a good while tinkering with the loom so had figured out how to do it. 

I'm actually thinking of a plan B already, replacing the relay with a more conventional one and upgrade the low beam lights to take the load off the switch. Much like the boomslang ones but built in. A few details to figure out but I think it could work. 

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@mmgemini posted a how-to-do-it thread in here years ago I'm sure. This relay-switches the loads. I copied it exactly and shorted out the dim/dip relay. It suggests fuses and relays for dip and main under the bonnet on the side of the n/s wing.

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I used this diagram to make my own loom to add relays for dip & main beam, uprated the wires from relays to headlights, took the 12v power supply direct from alternator terminal, changed the headlights to new crystal lens bowls & osram night breaker lights 

IMG_20190601_205709.jpg

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12 hours ago, Peaklander said:

@mmgemini posted a how-to-do-it thread in here years ago I'm sure. This relay-switches the loads. I copied it exactly and shorted out the dim/dip relay. It suggests fuses and relays for dip and main under the bonnet on the side of the n/s wing.

I did 

Here it is again, no posh drawings tho  https://www.tapatalk.com/groups/landytown/headlight-wiring-a-better-way-to-get-light-t7578.html

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Can’t see a problem with keeping the dim dip as they say every little helps, 

only problem I have with mine is that resistor gets bloody hot 

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Dim dip is no longer a legal requirement it was ditched back in 2006, drl's are much better & more reliable, I removed my dim dip years ago, as it kept failing. 

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So the morel of the story is if they are working let them be,

i have built in DRL’s on my front bumper love the look of them going to put the relay in by the fuse box this time round instead of under the bonnet run the cables in trunking along with the led light bar make it look professional 😂

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On 6/2/2019 at 9:57 AM, Green200tdi said:

only problem I have with mine is that resistor gets bloody hot 

That would explain why LR went to the trouble of putting it under the bonnet when the rest of the circuit lives behind the dash.

I think I'm going to delete the dim dip relay, join the Blue/red wires and add a new relay down by the fuses, along with a dedicated power feed in from the alternator and bigger wires out to the lights. That way the relay gets to live in the (relative) dryness of the cab, and I can use the existing fuses for neatness. As part of the delete I'll strip out all unnecessary dip dip related bits from the loom.

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So I've stripped out the dim/dip circuit from the loom, next part is to sort out relays for the main and dip beam. I'd like to put these at the fuse box down by the other relays, the bases for which I see are helpfully interlocking.

Can anyone point me in the direction of the correct interlocking relay bases, and some suitable relays with dual 87 pins (so I can run each bulb on it's own wire direct from the relay)?

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Have a look at polevolt or autosparks or vehicle wiring products websites, 

I used 2 relays, one for dip & one for main feed by fuses from alternator 

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Posted (edited)

Dave, the relay bases from Vehicle Wiring Products that are for standard 40A switching relays do interlock with the yellow bases that are down there at the fusebox. They also have a mounting tab with hole and I used this too at one end of that row. (I fitted three additional ones I think).

The headlamp upgrade that I did used 70A relays. These have big blades ~9mm I think rather than the ~6mm and I think the relays and bases are physically bigger. They do interlock but I don't know if they will fit down at the fuses. I think this is the base I used.

Mine are in the engine bay and appear to be holding up well (over four years now), with dumdum and other sealing.

IMG_9323.thumb.jpg.57223181977c66fa42cadcb910efdc32.jpg

 

Edited by Peaklander
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Posted (edited)

Thanks Peaklander, good to know the black ones fit, I've seen those available all over. I understand the relays I need too, but every supplier seems to give them a different name (double, dual, twin, special) which makes searching for them tricky. 

Anyway, before I add more relays I want to understand what the existing ones do. Excluding the Flasher unit and wiper delay, I have 4. 2 are fairly obvious, 2 I have no clue on. 

DSC_1415.thumb.JPG.43550e061021cfc2c9a852b326f322b4.JPG

From left to right. 

1. Changeover

30 black

85 black

86 red/white

87 slate/red

87a black

I can trace the slate/red which goes up to a small female spade by the warning light panel, and back down to a multiplug engine side. No idea what this is for. There is a white/yellow close by that takes the same warning lights to multiplug route which is also a mystery. 

2. Changeover

30 white/purple

85 white

86 white/brown

87 white/red

87a white

 

3. Headlights. Is this to stop the headlights coming on with the ignition off? 

 

4. Starter relay. 

 

Any ideas? 

Edited by daveturnbull

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I can’t see my electrical drawing as away from home today. I would normally do a search of the pdf for the wire colours and see what they do that way.

My 300TDi has a heated rear screen on the third relay from right. The colour for that is white black I think. There’s only five relays there in total though: Starter/ Headlamps / HRW / wipe and flash. 

So that’s not very helpful. 

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Looking at my 97MY diagram isn't any help as the SR wire is for Transmission Oil temperature warning and WP is for fuel pump. So I can safely say that they aren't going to be the same on your 200TDi loom.

I do have an old 300TDi drawing but that is stored as a picture so it can't be so easily searched.

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Poor documentation is largely the problem I am having identifying wire functions. It appears that TD5 looms are really well documented, 300 Tdi are OK, but 200 tdi or earlier all there seems to be is a bad scan of a partial loom from an old oily workshop manual. 

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I have an unmolested 200TDI sat out the back, and have just checked the relays.

It has the first mystery relay (with the slate / red

Two yellow holders, one green.

This vehicle is a 1994 110 panel van. (Ex electricity board built by Landrover SVO)

Will look and see if I can find the Slate / Red in the engine compartment.

 

 

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Posted (edited)

Slate red seems to terminate at one end of the 10 way chassis loom plug.

One of two raised terminals.

This is the only terminal that does not have anything plugged into it, so not greatly helpful.

Edited by MR-HIPPO

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Yes, same as my loom. 

Looking again at the TD5 warning light conversion guides, there is a SR which goes to pin 5 on the 16 pin plug and is for the gearbox temp. It's an earth, which may explain the need for a relay too. I'm sure that LR could have made this circuit a little simpler, especially with all the inline resistors it seems to have. I doubt I'll ever use it, but have stuck a terminal on the end to put in the plug so at least it goes somewhere. 

Next mystery, what does relay 2 on my picture above do? 

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Posted (edited)

You beat me to it.

I have just been testing mine with a test lamp (all I had to hand)

Earthing the engine bay side of the SR does indeed illuminate the Transmission temp light.

Earthing the fusebox end of the SR illuminates the Trans temp & Brake fluid level lights.

White red, is the ignition switch side of the crank engine circuit.

When you crank the engine, the relay provides a path to earth for both the Trans temp & Brake warning lights, causing them to self test each time the vehicle is started.

I assume it was a commercial vehicle thing.

Not greatly helpful now, but It explains the overcomplicated circuit, and use of a relay.

 

I would also like to get the Transmission oil temp light connected to a gearbox switch on my TD5 clocks.

Good luck with the other relay.

Edited by MR-HIPPO
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Excellent explanation, thank you. 

I'll get the loom back on the dining table when the wife is out next and trace the wires on the other mystery relay. 

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Well she didn't go out, but I braved it anyway. 

Pin 30 (supply) is the white / purple, this goes to the magical mystery 8 way connector in the engine bay. Pin 85  (coil live) is white, ignition live and looped to pin 87a. Pin 86 (coil earth) is white / brown which goes to the oil pressure warning light (which is an earth). Pin 87 (load) is white / red and joins into the main white / red feed. Pin 87a (load 2) is white. 

I did find a suggestion that white / purple is possibly for the fuel pump. 

So, any suggestions? 

DSC_1416.thumb.JPG.e20032f1ce2fc64a1258e09a6f18ae15.JPG

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I popped over to see my local friendly specialist at lunch time, and have a raid of his wiring graveyard for some relay holders. I also had a look at his big book of land rover looms and discussed what this relay is all about. 

White / purple does indeed seem to be related to the fuel pump and / or coil power feed on petrol models. His explanation was that it cuts the power to the spark / fuel circuit whilst cranking AND the oil pressure light is on, thus preventing the engine from being started until the oil pressure light goes out. Seems to make sense, even if the supply / load are wired in backwards to my mind.

So it looks like my loom was from a 200tdi era petrol model. My question now is, does a non-petrol loom of this age have a white / purple wire at the multiplug? And if not, does the oil pressure warning light wire (white/brown) just go straight from the multiplug to the warning light panel? I'm considering stripping the circuit out if it's not required.

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