H5 to H4 conversion-wiring harness adapter
 

I recall seeing a thread about converting H5's (as would be on a G50 Carrera 3.2) to H4's requiring an adapter for the plug to convert from the round H5 plug to the square H4 plug. Does such an adapter exist as a premade thing or do I have to make one? I tried to search but H4 and H5 as search terms are too short.

TIA

bump

The plug you need is available at Auto Zone, Pep Boys, Napa, etc. The 9004 H-4 bulb has three spade connectors which are 90 degrees to each other. The connector that you need has corresponding female recesses for the spade plug-ins from the bulb. Just cut off the H-5 connectors and splice in the H-4 connector, making sure to get the wires correct. One wire is the ground, one is the high-beam, and one is the low-beam. Twist them together and check before you solder them up. If your car doesn't already have it, wire in some relays for the low and high-beams. This eliminates the voltage running through your turn signal harness that will eventually burn it out. I think that they're available through our host. If not, do a search for "Marcos Sucro." He sells a very nice two-unit relay that's assembled and ready to pop in.

Steve

If you don't want to cut off your connectors, Then you need to make a adapter. All you need is a female h4 to a male h5. Google the h5 and h4 connectors. Also use the search here

If you plan to put in some of the higher wattage bulbs available, plan on upgrading the wiring to 12 awg. You will see how questionable the OEM wires are when you get in the bucket. Also use the Hella H4 HD socket from Daniel Stern Lighting if you go this route.

The relay kits mentioned can also be easily self-made for 2 & 4 overkill relay banks. I made an overkill 4 relay bank. You can also wire the city lights as daytime running lights although I understand that this is (stupidly) illegal in some states.

Some past links can be found on my links page. See Headlights - H4 Upgrade under Electrical for lots of reading.

Ian

brilliant, thanks all.