In a change of course related to this query of mine, the more I read about headlight bulbs, it seems that many are gimmicks and don't offer any real-world improvement. So, I will likely just stick with stock but go with something like GE Nighthawk bulbs (1) or similar. I am also replacing the driver-side headlight assembly as it's got that glazed-over covering.

Anyway, I didn't realize it until someone commented in the above-linked thread, but when you have the high-beams on in this model, BOTH the high and low beams are on at the same time (explains the 20a fusing per side). Now, both low beams work and both high beams work, but when the highs are on, on the passenger side, the low doesn't come on at the same time. What would cause that ? A relay ?

(1) I will read up more myself, but any comments on the differences between the standard Nighthawks, the Sport version, or the Platinum version ?

 

hmmm. so all work on both sides separately, but on one side they don't both work at the same time?

i agree a relay is the first place to look.

 

Yes, I can confirm that all (4) bulbs light at one time or another. So, the bulbs themselves are fine.

Which relay ? There's "Lighting Relay 1" and Lighting Relay 2". Can I test existing ones ? I have a multimeter - I presume only checking for continuity.

Interestingly, there's a 7.5a "Dimmer Relay" (it's labeled "relay") missing but the plug for it looks like a standard mini-fuse.... Is that because of the low amperage rating ? Or am I confusing this "dimmer" with maybe the interior lights that can be dimmed ?

 

I've been Googling off and on since yesterday... Are these relays Honda-specific or are they like flasher relays, somewhat universal ?

 

I moved your thread to get you more views and possible responses. I will also try to give some input.

 

Your headlights may be functionally normally.

A1. Headlight Relay 1 controls the right headlight (high and low). Headlight Relay 2 controls the left headlight (high and low).

To test the relay, check for continuity between the terminals. However, from a quick look at the parts diagram for your car, most of the relays in the under-hood fuse/relay box are the same type; so, most are swappable.



A2. That fuse slot is unused and goes no where.

A3. The headlight relays for your car appears to be principally made for Honda/Acura. Omron, Siemens, and Wells are some of the manufacturers.


The following is a description on how the circuity works on your EX. U.S. version EX are different than DX and LX. EX circuit had the auto-headlight off feature.

High and Low Beams

The headlight relays receive battery voltage at all times, and on EX Models are controlled by the driver’s/passenger’s multiplex control unit. When you turn the headlight switch to the HEAD position, ground is applied through the BLU/RED wire to the coils of the headlight relays. The relays are then energized, applying battery voltage to the left and right high and low beam headlights through fuses 43 and 45. The low beam bulbs come on with the dimmer switch in LOW or HIGH because the opposite terminal is tied to ground. The ground path for the high beams and indicator is through the dimmer switch. With the dimmer switch in LOW the path is interrupted and the high beams remain off, but in HIGH a ground path is provided and the high beams come on.

A dimmer switch of sort suppose to be incorporated into the combination light switch. Can you take a picture of the combination light switch from your car and post it?

 

You may just have to change the dimmer switch setting on the combination light switch to High.

 

First, thank you for that excellent/detailed response ! Here's what they look like (I may have the high and low beams reversed, but no matter). "x" = off, "0" = on

Low beam
(0)(x) (x)(0)

High beam
(x)(0) (0)(0)

Does that make sense ? What do you mean by this combination light switch ?

When you answer the above, this one will probably make sense !

 

High beam
(x)(0) (0)(0)

1. Ok, your illustration does show something wrong.


2. The combination light switch is the stalk. It may be okay since the low and high come on, at least on that one side.

 

Disregard what I posted regarding the dimmer switch. My brain and memory wasn't working for a bit.