Matt Jones

Just bought a beautiful red 89 rx7 convertible, killer price, but the dash lights, turn signals, running lights, and brake lights don't work. Fuses are all good, and the car has an aftermarket stereo and alarm. Any suggestions ?

satch

iTrader: (1)

Start w/something simple such as the brake lights. Switch on the brake pedal has two wires. The Green/White wire must have constant voltage to it. Does it? If it does then depress the pedal and then the Green wire in the two wire plug should have voltage to it. Does it?

Matt Jones

I will check when I get a chance, I find it hard to believe this is coincidence, is there any single component that would fail and cause this? This ONLY lights that work are interior door and map lights, and headlights. No other lights work. No brakes, tail, running, or dash lights work.

Aaron Cake

iTrader: (1)

Why can't it be two blown fuses? Check room fuse, and whichever one does the exterior lights (I forget).

Matt Jones

I don't believe in coincidence lol. And I did, they're illum and stop down by the pedals. The fuses look fine, and I switched a few around to test. Those are all good.

satch

iTrader: (1)

The tails, running and dash are all part of the headlight switch while the brake lights are a different circuit. The headlight switch powers the Red/Green wire which illuminates the dash and gauge lights while the switch also powers the Red/Black wire which powers the tails and running lights. The switch grounds a wire at the headlight relay causing the headlights to turn on so you can easily have some lights working but not others.

Matt Jones

Sounds like I should start with the switch then. Any helpful suggestions or things to look for this amateur car mechanic? This is my first car that isn't a Chevy truck and I'm a little bewildered.

clokker

iTrader: (2)

The brake light circuit is much simpler and probably a better starting point for a rookie.
If you haven't already, download the factory service manual here.

The easiest approach to the light switch is the time honored "Try another one" method.
Sadly, being a new owner, it's unlikely you have a spare in hand (TopTip: if you ever run across FC switchgear on CL or the junkyard, grab 'em. Our switches are completely unique, expensive as hell and prone to failure. You have been warned.), so prepare for your 1st Full Satch experience. Make sure your multimeter is ready.

satch

iTrader: (1)

Start w/the simple stuff. No, don't start w/the simple stuff. Well on second thought start w/the simple stuff. You know the brake switch!

Matt Jones

Okay so the green and white brake wire does have voltage. The other wire you're referring to, I presume its the smaller red and green wires jumped together that are in the same bundle of wires near the brake switch. The aforementioned red one is powered, the green one doesn't get voltage with or without the brake pedal depressed.

satch

iTrader: (1)

The brake switch is connected to a plug w/two wires and one of them is Green. Not sure what other wires you are referring to but the Green wire which is part of the switch has voltage w/the pedal depressed. If the voltage from the other wire in the switch (G/W) is jumpered to the Green wire then the brake lights ought to illuminate.

Matt Jones

I was able to pull the the light switch. Doesn't appear to have any scorch, burn, melt marks on wires, harness, or receptacle. Anything I can test with my multimeter to confirm? Or anything I can jump in the car to get lights to turn on now that I have this thing out?

clokker

iTrader: (2)

A quick guess might be wires for cruise control which, if not installed at the factory, are just bundled in the loom.
Colors don't sound right though.

satch

iTrader: (1)

White/Green has constant and Red/Black has power w/**** turned to the 1st position. If W/G has power then jumpering voltage to the R/B (that's Red/Black and not Black/Red) should cause the gauge, dash, driving and tails to turn on). If so, then switch is kaput if the 1st statement is not achieved.

Matt Jones

I think you're right, the plugs are close to each other and I mistook them for being one plug. I have figured it out, the brake switch seems to be bad. The green and white wire is powered, but when I press brake pedal, other green wire (looks like green and yellow maybe) doesn't receive voltage. I'll have to find something around the house to use as a jumper to confirm, but I'd just jump the two greens in that harness together right?

satch

iTrader: (1)

G/W to G. The switch only has two wires so there's really no unknowns here.

Matt Jones

Will also be sure to try this when I find something lying around to jump with. You guys are lifesavers, I would be so lost and upset without your help. Thank you so much Satch and clokker.

satch

iTrader: (1)

All you need is a short length wire bare on both ends or you could just use a paper clip.

clokker

iTrader: (2)

The brake switch may just be maladjusted.
It screws in and out of it's mounting bracket to set when the light is activated.

clokker

iTrader: (2)

It's the reverse, satch.
The plunger is normally pressed in, pushing the brake pedal allows the plunger to extend and the contacts to close.

satch

iTrader: (1)

You're right. And now it's time for a delete!

clokker

iTrader: (2)

That's a useful power to have.
Could you delete my second marriage?

misterstyx69

iTrader: (142)

..should have listened to the guy that said "don't EFF around with something that bleeds for 5 days and doesn't die".
I miss my wife...I think it is the degree of angle when I shoot at her.

Matt Jones

Would you be able to provide me the pinout for the light switch? And, in theory, could I pick up a toggle switch and rig the driving lights and the headlight relay to the power wire? Just to get around until the new switch comes.

satch

iTrader: (1)

The two wires are next to each other and they are the only wires of this color in the plug. And you could add a flip switch to bypass the possibly defective switch. W/G should have constant voltage so you check that first. If it does then you measure for voltage on the R/B wire w/the switch set to the first position. If it does not have voltage then the fault lies within the switch. If the wire does have voltage then the issue is further down the line perhaps at an intermediate connector known as X-17.


Foxed.ca - Mazda RX-7 Manuals (bottom right of page E-3)