Bosch H5 to H4

[rford3678]

I just discovered that the H4's that I was told were in the car when I bought it
are actually H5's. From what I have read not as good in regards to the H4's.
Would swapping them out be a easy thing or would there be wiring issues?
(different connector, etc.) Does anybody have an opinion on the H5's compared to the H4's. Any advice appreciated. Thanks.

rford3678
85 Carrera
(newbie owner)
will post some pics when the weather clears

[logan2z]

I just did the upgrade from H5s to H4s on my '87 Carrera. The H4s are considerably brighter than the H5s, although the difference may have been a bit exaggerated in my case since my H5s were pretty foggy (despite a good cleaning with isopropyl alcohol). An adapter was required between the headlight wiring in my car and the H4s, but I believe that's year-dependent and that may not be required in your '85. I'm sure others more expert in the subject can verify.

I just swapped out the stock bulbs for 80/100W bulbs for even greater brightness (purchased from our host for $9 a piece) and this required the installation of relays to prevent melting the wiring for the headlight switch. These bulbs are super bright and really light up the roadway at night. All in all I think the H4 upgrade is well worth it.

[myamoto1]

rford - I did the same thing on my '85. Here's a post of what I did, which includes a link to the wiring diagram:

Coverting from H5 to H4 headlights

[tcar]

I believe even Pep Boys has the adapter plugs.

[donporfi]

You will need two connectors, a male to connect the existing connector (the one that connects to the bulb) and one female to connect the new H4 bulb.
for the harness:

for the H4 bulb


You can buy these from Susquehanna MotorSports - High Performance Vehicle Lighting and Competition Accessories (no affiliation)

[rford3678]

Thanks, this is very helpful. I found the connectors at that website without a problem. Hopefully this should go ok.
Thanks everyone again for the advice, I do appreciate it.

rford3678
85 Carrera
(newbie owner)

[mikehinton]

Make sure that if you run high-wattage bulbs (e.g. 55/100) that you install the relay kit available from out host so that you don't fry your switch.

[myamoto1]

+1 on the relay kit - I installed mine only after having to pull apart my high beam switch. Haven't had an issue since.

[m110]

A great upgrade, use the relay kit, bright bulbs, looks good....safer (I think) because you can actually see, not just because it's brighter but because the beam is aimable and better focused.