4g alternator info by arif_manji

Post by **Drax** » Thu Mar 03, 2022 2:04 pm

The UKDM and JDM's have different alternators and have a different charging system. It also means they have different engine fuse box. The JDM Prelude’s have a 3 pin plug to the ELD and the UKDM’s have an inbuilt one.

I've noticed that on the UKDM, the alternator plug is:
S FR
IG L

The JDM is:
C FR
IG L

The alternator code to look out for is:

UKDM = S means Sensor.
JDM = C means local charge output.

K30DPC · Post by **K30DPC** » Sun Apr 03, 2022 9:03 am

I'm in need for regulator now. All I can find is for JDM. Did you find any supplier of UKDM parts?

Alternatively I have JDM fusebox and could swap it. What other changes need to be made to make it working?

Post by **Drax** » Sun Apr 03, 2022 11:12 am

K30DPC wrote: ↑
Sun Apr 03, 2022 9:03 am
Did you find any supplier of UKDM parts?

viewtopic.php?f=4&t=31417

K30DPC · Post by **K30DPC** » Sun Apr 03, 2022 9:06 pm

Thanks Drax. I've seen this already. I wish it was that easy. Unfortunattely there is loads of regulators available but all with 'C' output and my car required 'S'. I think it will end up with new alternator. I know @arif_manji had issue with this as well.

arif_manji · Post by **arif_manji** » Fri Apr 08, 2022 6:48 pm

Hi @K30DPC,

Yes the alternator will have to be like for like. The UKDM's (in my experience) has been an absolute pain. I had one from a UKDM 2.0i and 2.3i and they also didn't work for my 2.2i VTEC. It will have to be from the same spec Prelude you have.

I think the best solution if you can't find a replacement is to have your refurbished.

Let me know if you need any other info.

Cheers

Hagland-BB4 · Post by **Hagland-BB4** » Fri Apr 08, 2022 7:10 pm

I am in the same boat.
been quoted £140 to fix

K30DPC · Post by **K30DPC** » Fri Apr 08, 2022 9:33 pm

In my case all started from dash charging light not coming on at all which made my remote engine start going crazy. I found it was alternator not sending ground signal. So after investigating the whole thing I found rectifier being shot and ordered one. I've done all testing as per manual, and other parts looks good, but there is no way to test regulator. Manual states to test all and if it still doesn't work as should than change regulator.
At the moment I'm waiting for rectifier, but I strongly believe that I will need regulator as well as it's electrically connected to the engine/chassis/ground, it takes 12V power supply and ignition signal through the connector and I can't see why it wouldn't send signal for engine not running only because of rectifier being faulty.

I'll report when postie will bring rectifier. Somehow I hope it will fix the issue as it seams them regulators are not available at all.

On a side note I would apreciate if anyone have JDM wiring schematics for 4 gen. So I could compare what need to be swapped to use regulator with 'C' output