kiker14

iTrader: (1)

Hi Everybody,

Lots of times when I'm researching issues on here I wish that people would post pictures of their issues. So, going forward every time I find something wrong with my car, and fix it, I'm going to post pictures to help people out.

That being said, the other day I noticed that my dash lights were not working. I still haven't had the car that long, and I know that my headlights are not fully functioning (high beams don't work, I'm assuming the CPU is bad because flash-to-pass works with the switch) so I haven't been doing much night driving. In fact, this was only the second night. The first time I did some night driving the dash lights were not bright - but they worked. Two nights ago, just blackness.

I did some research and found out that the connection at the switch can get burnt. Why the fuse does not blow first is beyond me - but that is what happened to me, the fuses are fine, but the harness and the switch both melted together. As an FYI when you are taking apart the dash cover, it is almost impossible to get the harness plug out if it had burnt. I ended up unplugging the harness on the side of the kick panel then taking the gauge cover off with the harness still connected to it. For what it's worth I also removed the turn signal switch and cruise control switch but did NOT remove the steering wheel - one quick movement and the gauge cover "popped" out. Getting it back in will be fun...

Once it was out I used a pair of vice grips to get the plug out - and even then it required some "umph". It never would have come out by hand, and certainly not while still installed in the car.

Here are some pictures of where it failed. You will see a melted "ring" around the pins - I fear that they are going to cause me issues going forward so I'm going to get a new switch plug and harness. As this is my hobby car and I'm over budget for the month I will have to wait a while to buy the new parts unless somebody has an extra they want to sell me very cheap.

Here are the pictures...












And under the dash... could somebody tell me what that small blue plug is supposed to go to? It was just hanging out down there...

87 t-66

iTrader: (133)

looks like that blue plug is part of the airbag system...

maac0953

good job dude. iam gonna check mine soon to to see if its the same problem too cause my dash lights dont work either since i bought my car

kiker14

iTrader: (1)

wonderful. Do you by any chance have any pictures or could you describe to me where it should plug into? Since I have an airbag I might as well have it active...

87 t-66

iTrader: (133)

i dont remember exactly...if you take your steering wheel off it should be easy to trace the wiring. there is an orange and blue plug that are behind the steering wheel and go out into the engine bay.

RotaryRocket88

iTrader: (7)

I'd say before plugging anything into the air bag, check the FSM for the correct wire colors. If this plug is wrong, but happens to fit, and receives power for any reason, you're liable to set the airbag off in your face. Not gonna be fun.

kiker14

iTrader: (1)

agreed - I will do that and will get back to everybody - again, I will post pictures for future reference :-)

Pele

iTrader: (28)

My harness was the same.

A new harness from Malloy Mazda is $110.
A new switch is remarkably more expensive.

And to top things off, new parts are only a temporary fix. You have to add a relay to the harness for a permanent solution.

Your dash lights and tail lights will both be on that wire and both will not work.

87 t-66

iTrader: (133)

the connectors for the airbag are different than any others on the car. they are very noticeable. i wonder how long those things usually last? i took mine out because i don't trust it.

RotaryRocket88

iTrader: (7)

They probably are still good, but it's kind of something you can only try once.

rx7_FREAKKK

iTrader: (1)

I would think before the switch over heats everyone should take the switch off and put some electro lube on the contacts before this issue comes up!?

20Bforme

is there any write ups for this? id like give this a try this week sometime.

j9fd3s

iTrader: (3)

the headlight switch wiring problem is known, they NEW parts are updated. its actually a bigger problem on the s4's

kiker14

iTrader: (1)

I also sent pele a PM to see if he had more info. I would also like to tackle this one on my own. I am assuming you just throw a relay on the wire in the harness that has the problems, but I'm not exactly sure how to power the relay so hopefully he can enlighten us, and I will take pictures of my progress once I tackle the project...

kiker14

iTrader: (1)

once again icemark (RIP) to the rescue...

https://www.rx7club.com/2nd-gen-archive-72/heavy-duty-light-switch-operation-how-too-prevent-burnout-164931/

I'll be following his instructions in the archived thread, but I will also include some pictures just for fun. I will probably be doing this next week so stay tuned :-)

kiker14

iTrader: (1)

and while I'm at it...

https://www.rx7club.com/2nd-gen-archive-72/write-up-rebuilding-your-headlight-switch-383384/

has information on how to rebuild the switch. Tons of pics already on that thread which will be very helpful, but again I will be taking some of my own as well

Pele

iTrader: (28)

That's the stuff. Here's the skinny: My FC (Early 1986 GXL), I hauled out of some guys yard after sitting for two or three years.

It had several electrical problems that FCs are known for:
1.) Wiper only works on Low. (Fixed, replicated on another car - successful the first time.)
2.) Clock didn't work. (Fixed, replicated on another car - successful the first time.)
3.) This problem; No dash or marker lights.

I followed Icemark's write up, but I used a relay socket salvaged from another vehicle and I wasn't paying attention to color codes. I ended up screwing it up slightly...

I pulled the wrong pins from the Mazda wiring harness and hooked up the relay backwards. It was an easy fix, but with so many wires it's easy to get confused.

I have since learned how not to do it. Now I have a supply of the proper relay sockets and have replicated it on the other car (1988 GTU)...


You want to follow the instructions in the writeup to the "T"... Make sure you know what relay contacts you are connecting to what.

I really can't add to Icemark's write up. Just work slowly, and doublecheck yourself before you solder and add the weatherproof shrink tube.

kiker14

iTrader: (1)

So, I followed Icemarks instructions and took pictures along the way. After looking at the instructions for rebuilding the switch, I figured I would just try to use the switch as it was - a closer inspection showed me that the switch connection where it melted was really just black plastic from being melted, not metal so none of the pins were touching each other.

http://www.radioshack.com/product/in...ductId=3020762 is the relay I used

and I didn't want to have to solder right on to the relay so I got connectors (18-22gauge connectors, comes in a pack of 10 with 5 male and 5 female)

Here are the pictures...

Supplies:



Tools and harness (I cleaned the connector on the harness with a skinny
sharp tool)



::sigh:: this was the broken wire



little wires with connectors for the relay



The same tool that I used for cleaning the harness pins was used to stab the wires that needed tapping...



Then you can see I put the wire that I needed to tap through the hole I made (note that this black wire is going into the harness where the white / green wire used to go, but it was too weak at the connector so I had to solder the new black wire in to the point where the white / green one was)



Everything put together and soldered tight before getting electrical tape



Plugged the wires into the appropriate pins on the relay as per Icemarks instructions (I trust his instructions, didn't even bother to look at a wiring diagram...)



Reinstalled it...



And SUCCESS!!!



nice bright tails...



I didn't fiddle with my camera but the lights are actually nice and bright, and the dimmer works great too



I wish Icemark were around so I could thank him for his instructions, they were great, hopefully these pictures will be a nice compliment to the instructions for somebody!

87 t-66

iTrader: (133)

nice! good job

20Bforme

so you re-used your old switch? and it worked?

HAI-TEK7

iTrader: (31)

Nice!

kiker14

iTrader: (1)

Yes, I reused the harness and the switch so the whole project was about $8 and a trip to radio shack, but I got lucky - there was some corrosion that I cleaned out of the pins but I didn't even take the switch apart and yes, it still worked. I figured it was worth a shot to do a quick test before taking it apart to fix it and to my surprise it worked just fine, so I put everything back together and called it a day

20Bforme

ok... few questions...

is what you did basically the same for S4s?

how did you release the blue plug from its bracket?

why does your harness only have one plug? (an S5 thing?)

satch

iTrader: (1)

Another question. If you did not remove the harness from the lightswitch could you have disconnected the harness at the blue plug( the other end) and done the job while it was still in the car? Did you also take precautions and disconnect the battery beforehand?

Pele

iTrader: (28)

You may be able to get away with a melted old harness. I say may because there are a few problems that will cause the harness to become unusable.

1.) The wire gets brittle and the insulation gets stiff and crispy. (When flexed, the insulation may break off and short out against something.)
2.) The wire gets all burned up and loses contact with the pin in the connector.
3.) The melted connector has the pin skewed so that it does not mate with the pin in the switch.

Sometimes, all it takes to get working again is a simple wiggle for those burned up pins to contact and the lights come back on... Of course without the relay, the pins will just burn up more. This is why Icemark suggested BOTH a switch rebuild AND a new harness.

While I wouldn't go as far as to suggest a new harness (Which as I said priced out at Malloy at $110) I would recommend carefully inspecting your existing harness... Flex the wire and make sure the insulation is not brittle. Make sure that pin doesn't wiggle around any more than the others... That sort of thing.

I inspect them for customers when the package arrives on my doorstep and let them know right away if I can or can't use it.

Yes, 100%. Both my 1986 GXL, 1988 GTU, and I've just done a 1990 GXL for a customer. All the same. Harnesses lines up and everything.

Slightly different pinout for S4 and S5, but Icemark's instructions apply to all.

Push forward and jiggle side to side.

That's a weird one. The customer that sent me a harness for the 1990 GXL bought it new from Mazdatrix, it was new in bag and it had two connectors.

I prefer the relays to be at the blue end. I keep the relay lines short so that the relay stays near the harness, and away from the speaker and up in the dash.

I usually zip tie them to the harness close to the support to that it doesn't flop around under the dash and vibrate or make any sort of noise.