I've just upgraded my 1989 90 to have LED lights all round. Just thought I'd share my "lessons", since when googling it, there's difference choices & options.

1. Headlights - I like the trucklite headlights because they look pretty close to original. I don't like the "lens" look that many of them have and the beam pattern on the trucklites is crisp and clear.
2. When you do the headlights, plan on putting new headlight bowls in too for a tidy install.
3. I got a full WIPAC LED lights setup - including sidelights.
4. Get a lucas terminal crimp connector, along with some econoseal connectors - so you can make stubs to connect the new style connectors to the old without hacking your loom.
5. If you want all the exterior lamps to be LED, then it's likely you will find when you indicate left, the right indicators flash a bit too, and the internal repeater will be dim. I tried the following:
* Re-ran new dedicated earths everywhere
*Tried the RDX LED internal repeater
*Put a dummy load on it.

I found, no matter what I did with the earths, I couldn't get it working correctly.
I then tried the RDX LED Repeater. It solved the problem, but the LED came out far too dim to be useful.
Finally, I have temporarily put a hidden 21W bulb, blacked out, connected into the rear loom (both in the rear LHS. This works perfectly. I now have a couple of ceramic resistors on order to do it tidily.

HTH.

Got to ask, Is it worth it? I found it caused more trouble than it was worth. Probable better to do the whole truck than just some like I did. Only led I have left lights my temp gauge.

I needed to replace them anyway - all old ones (33 years old) were all starting to get corroded and unreliable - regularly needing stripping and cleaning to keep them working.
So I probably wouldn't have replaced them "just because", but at the point they needed replacing anyway, I think replacing with sealed LED units is not a bad idea, for me anyway.

Green LEDs in the gauge lights is nice too, definately.

Do led headlights draw a lot less power?

Col

Yes. Full beam is about 2.3 amps on the LED (per side) vs 4.6ish on a 55W halogen. For a much better light beam & pattern too.

Instead of the resistors, you can put a couple of diodes in the circuit at the indicator dash tell tale lamp - this is where both sides of the indicator circuit are joined - just one tell tale lamp for both sides. The diodes just let power flow in one direction and effectively isolate the indicator side not in use.

I've all led lights except headlights. They are a great upgrade in my opinion. I'd like to get headlights done but can't justify the expense. Will probably go for wipac crystal lamps with nightbreakers and a relay switched feed.

The only Filament to LED changes I have don were the dash lamps. And the only issue I had was the -charging lamp, it wouldn't go off. So I put original lamp back in. Will look at fitting a resistor one day.