jpc90rx

I've got a '90 vert w/ no hi-beams.

I've looked at several threads in the archive related to this, and I've tried to track it down, but I'm still stumped. Here's the situation:

- Headlights work on lo-beam, but not on hi-beam (both lights)
- Hi-beam indicator does not light in dash when I toggle to hi-beam
- Flash-to-pass works fine, however (flashes lo-beams)...I was assuming this meant the switch was OK, since the same control that does this toggles the lo/hi-beams

Here's what I've checked:

- Replaced headlights (needed new ones anyway)...no dice.
- Tried the dimmer relay off my buddy's '90 vert whose hi-beams worked last time he checked (car has been parked for 6 months, however)...still no dice.

SO...

1. Is it possible that the headlight switch is bad, even though parking lights, lo-beam, and flash-to-pass all work?
2. Could it still be a problem with either the headlight relay or dimmer relay?
3. Is it most likely a wiring problem at this point?

Any insight would be appreciated.

jjwalker

My highbeams strobe with the seatbelt light. My alarm armed light will also strobe and beep continuously until I shut the door, which it then arms itself as normal.

If I hold my highbeam switch back, which lights on, the high beams will flash on and off the same time my seatbelt light flashes. To explain it another way, when my seatbelt light comes on in the dummy cluster, my highbeams will switch off. It is ******* weird and I have NO idea what could be causing it.

I have a 90 vert also.

kiker14

iTrader: (1)

I have the identical problem to the original poster, but have not done any troubleshooting yet. Some of my research found that it may be the CPU?

also '90 vert.

jpc90rx

I went ahead and ordered a headlight cluster switch off eBay...might as well eliminate that from the list of potential causes.

kiker14 - I sure hope it's not the CPU!

jackhild59

iTrader: (7)

I have struggled with this for 4 years. The problem is the latch circuit in the CPU.

You can buy 'used working' cpu's. I have done this and they always fail shortly after.

You can 'fix' the circuit and 'rebuild' the board. The late, Great Icemark told me that the FC66 was troublesome from the start and that he quit rebuilding them due to poor results and short life span.

You can buy a brand new full FC66 from Mazdatrix. Expensive.

You can replace the circuit board in the FC66. Mazdatrix sells the board for around $85.

You can mod your system like I did for a *permanant* fix. Here is the thread for your viewing pleasure.
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/s5-dimmer-fix-840197/

jjcobm

iTrader: (18)

Its the CPU. Get a new board from mazdatrix, on the s5 verts the highbeams are controlled by the cpu.

jpc90rx

jjcobm, jackhild59 - Thanks for the feedback, guys...I'll check into the CPU as well as the cluster switch.

(Why is it that nothing is ever easy on these cars?)

jimmy_trader

iTrader: (4)

Yeah, what jackhild59 & jjcobm said.
Q for jpc90rx & kiker14: When you try the switch, do the lights go out or just stay on low?
Sounds like the same problem I had. ( https://www.rx7club.com/2nd-generation-specific-1986-1992-17/my-hi-beams-work-842674/ )
My FTP worked with the lights down and off, but when I tried the switch, the headlights would just stay on low.
I got the circuit board from Mazdatrix(They got it from somewhere else. When I called to check the order status, they were waiting for it to come in so that they could ship it to me.)and now everything works.
If you can swap a CPU from a friend to test, that will prove/disprove if it is bad. Just make sure it comes from a car with an Airbag if you have one and w/o if you don't. (All '90 verts had'em, right?)
It's located down by your left foot from a driving position. A few screws and a couple wiring connectors.
jjwalker: I've no idea where to tell you to look. That's just weird.
Best of luck to all of you.
Aloha,
~j

jpc90rx

jimmy_trader - lights never go out, hi-beams just don't come on.

jjcobm

iTrader: (18)

Its not the switch, its going to be your CPU trust me, so get that ordered from mazdatrix..... (trying to save you some $$$)

http://mazdatrix.com/86-92Electrical-Chassis.htm

bc2262

Sounds like the CPU to me. I had the exact same problem with two different 91 'verts. Tried everything else first but learned my lesson. Bought board from mazdatrix - fixed.

jpc90rx

Thx for all the replies...and as several people suspected, it WAS the CPU after all. Got the one off the vert that Phearthe-Rx7 was parting out, plugged it in, and now they're working again. Sweet.

Thx again for all the feedback.

(Dang these cars have some strange quirks, don't they?)

HDP

iTrader: (2)

Having the same issues. Is the correct CPU board from Mazdatrix called "89-92 Horn CPU w/airbag" ?

satch

iTrader: (1)

The Dimmer Switch is responsible for sending a ground to the Dimmer Relay which causes the low beams to turn to high beams and vis versa. So if you place a ground on the White wire at the five wire Dimmer Relay while the lights were on and the lows changed to highs then you know the relay is good but the switch is not.

HDP

iTrader: (2)

Anyone?

satch

iTrader: (1)

Do you have a convertible?

HDP

iTrader: (2)

Yes...

jackhild59

iTrader: (7)

67-5640-fc66

andycivic

so i got the same problem im gonna do the push button switch thing but my other problem is my blinkers stoped working any way to fix that to??

jamesbaird

Hey all, maybe this thread can help me.

My 85 GSL hi-beams work when you pull back on the lever, but when you push forward to stay on permanently the headlights go out completely. Everything else works well, blinkers, flashers, interior, etc.

I am thinking it was the switch, but after reading this I have no clue where to start. Any help before I take apart me steering column?

Thank-you
-James