Hi All.

I'm about ready to install my euroheadlights. And I have a few questions.

I'm not the most electrical savvy, but I've done a few DC and AC projects. And I've managed to not burn anything down. Yet. ;)

I've gotten Daniel Stern's 9004 to H4 kit. Plenty of 12ga wire. Connectors, terminals, quick splices, etc. I've read plenty of older posts and I have Daniel Sterns upgraded h4 diagram.

My questions are: I want to wire in a redundancy using the old 9004 plugs. What would be the best way to go about that?

I'm also curious of where to run the hi/low signal output into the new relays for the upgraded circuit? Daniels diagram shows the signal going in/out through the firewall. If I can, I'd like to keep it all in the engine bay.

I'm gonna run the H4 lights off the battery. And besides these two questions it looks fairly straightforward. Thanks for any help you can lend.
--
'88 245,M47,Virgos,245K+

re: "...I want to wire in a redundancy using the old 9004 plugs. What would be the best way to go about that?..."

Okay, first I want to make sure I understand what you're asking (it may be exactly what I did).
I'm assuming that you have replaced your '86-on headlights with euroheadlights* which use the H-4 bulbs. You're using a set of relays to control the power for the bulbs through a parallel arrangement of heavier gauge wiring (compared to the car's OEM wiring). And you want to keep the OEM's plugs (rather than cutting them off), in case you ever have to reinstall the old, lousy headlights. Is that right? If so, this is what I did when I installed euroheadlights*.

First, I installed 10 ga wiring (both positive and negative) directly to and from the battery. I also used Dan Stern's high temperature H4 plugs (I hope you did, too). The positive cables are fused, and run through relays to control their current flow, while only needing negligible current through the car's OEM wiring. You can see my setup in the picture at the bottom.

Anyway, to answer your question, the easist way to control the relays, keeping everything in the engine compartment and also preserving your original sockets for the OEM bulbs, is to use small "mini" male spade connectors on a light gauge wire, and stick them into the sockets in the plugs, using these connections to control your relays. These mini connectors aren't the usual 1/4 inch variety you'll find at a neighborhood Radio Shack. You have to find a serious electronics hobbyist store (look up ham radio, or something like that in your search), but there are spade connectors of the right size to fit into the narrow sockets of the OEM plug. This will draw signal currents to activate the relays with very little amperage (hence the light gauge, 18 ga, wiring that I used), and if you use each side's connectors on a separate set of relays (one for high another for low beam) on each side (i.e., my right and left headlights are on separate relays, or four relays all together), like I did, you won't even have any problem with the light-out warning module because they'll be balanced.

[ * BTW, some of us use the term "euroheadlights" exclusively for the proprietary European lamps required on '86-93 cars, to distinguish these from those replacements for the generic sealed beam-style of headlights (for pre-'86 cars) which we call "e-codes". This, of course, is just a personal preference, but it helps avoid confusion sometimes.]

Below is from my late-version (hence the fuses on the positive battery clamp) '93 240. Don't be distracted by other things (e.g., the DRL module and extra relays for fog lamps, etc.).

Couple quick notes:

These relays don't draw enough current to trigger the bulb failure sensor. I've installed relays asmetrically on three cars (for a total of four separate bulb sensors) and haven't had a problem yet. Two dual-87 relays is all you need.

Easiest fool proof way to tap the factory 9004 plugs to trigger the relays is to use a "female" 9004 adapter. Dan Stern's kits should ship with these.

Finally: Nice wiring! Were do you find that neat looking terminal on the negative battery lug?

Thanks!
-Ryan
--

Athens, Ohio
1987 245 DL 324k, Dog-hauler
1990 245 DL 142k M47, E-codes, GT Sways/Braces, Dracos, A-cam
1990 744GLE 189K 16-valve
1991 745 GL 304k

Hi.
Thanks for the kind words :-).

Q: "...These relays don't draw enough current to trigger the bulb failure sensor. I've installed relays asmetrically on three cars (for a total of four separate bulb sensors) and haven't had a problem yet. Two dual-87 relays is all you need...."
Good to know, but I don't feel too bad having "overdone" it with redundancy. It gives me some backup, so if a relay should fail, at least I've got working lights on one side of the car.

Q: "...Were do you find that neat looking terminal on the negative battery lug?..."
Almost everything (unless I needed something special) is marine-grade -- i.e., the wires; the crimped-on, plastic coated and adhesive-sealed connectors (including the one you were asking about); and the fuse holders. The only exceptions are when I couldn't get it in marine-grade such as the mini-spade connectors for the 9004 plugs. For marine-grade connectors, wires, etc., go to WestMarine's website.

Q: "...Easiest fool proof way to tap the factory 9004 plugs to trigger the relays is to use a "female" 9004 adapter. Dan Stern's kits should ship with these...."
When I did this project, there weren't any such thing, or at least, he didn't have any at the time -- darn it, it sounds like a good idea, and I'll remember it for the next time. Thanks.

Thanks!

Despite having grown up around boats, I never considered West Marine! :-)

Indeed, marine grade stuff is best... and most foolproof. I usually aim for marine grade stuff... though most of my non-Bosch terminals come from the trailer aisle of Tractor Supply these days.

Next time: West Marine!

Thanks!

-Ryan
--

Athens, Ohio
1987 245 DL 324k, Dog-hauler
1990 245 DL 142k M47, E-codes, GT Sways/Braces, Dracos, A-cam
1990 744GLE 189K 16-valve
1991 745 GL 304k

Finished wiring up the E-codes on my 745 today, which is the third Volvo I've done this on.

I don't think it's worth the bother of wiring a redundancy. Have not needed to worry about it after 5 years.

Indeed, you can keep it all in the engine bay.

Here are some pics of the relays wired up in the '87 245:

http://www.ohio.edu/people/ridgely/for-buck/

-Ryan
--

Athens, Ohio
1987 245 DL 324k, Dog-hauler
1990 245 DL 142k M47, E-codes, GT Sways/Braces, Dracos, A-cam
1990 744GLE 189K 16-valve
1991 745 GL 304k

I'm just gonna splice the existing 9004 via adapter into the new H4 plug (y it with the new power wires). Then y the drivers side 9004 hi/low signal into the control signal of the new hi/low relays.
--
'88 245,M47,Virgos,245K+

Well that didn't work at all. I subtracted my wanting to do a redundancy, because I tried it, and it didn't work. :)

I'm not sure what a 9004 to h-4 kit is. If you are putting cibies in to replace sealed beams you never had a 9004 plug. Although I think a 9004 to H-4 bulb adapter would be a good idea my understanding is that Daniel Stern is vigorously opposed to it, and doesn't supply such a kit. So, what do you have?

Hey John,

They're the 86-93 capsule light e-codes, replacing the crappy yellowed plastic ones. Not the earlier style.

No, I have Sterns' kit. I'm running the new h4 bulbs straight off the battery. I'm just using the 9004 adapter as a fail safe redundancy and a low/hi signal for the new relays.
--
'88 245,M47,Virgos,245K+