MAZDA5 brake light malfunction

C

cplhornby

Member
:
2006, MAZDA5 sport, 5spd
Hi everyone!
This is my first post so bare with me here...

I have a 2006 mazda 5, 5spd with cruise and I love it!

My problem is that my brake lights are shorting out, but turn back on when i turn the car off and then back on.

I can tell it has shorted out when i turn on my cruise control. the yellow light will come on letting me know that i can set my cruise, and when that light turns out on its own I know my brake lights are no longer working.

Has anybody had this problem? Help please, the few mechanics Ive talked to say it will take 1 -2 hours to diagnose, however one did say it might be something called a break lamp switch which is located under the break pedal.

PLEASE HELP ME!!!
 
If you bought it new, it is most likely a relay. The Mazda5 manual can be downloaded if you know how to trouble shoot it yourself. Always check the Mazda3 threads and forums... They have similar issues:

5. Brake Switch Replacement

a. Locate the switch right above the brake pedal as shown.
b. Disconnect the electrical connector by pressing on the release tab;
c. To remove the switch, twist it like an 1/8 of a turn as shown, then pull it out;
brake_switch.jpg


d. Apply reverse procedure to install the new switch.
 
You rock

Thanks for the speedy reply and excellent pic to go with it. I will buy the part tomorrow. Im sure it doesnt matter that its a five speed?
 
cplhornby said:
Thanks for the speedy reply and excellent pic to go with it. I will buy the part tomorrow. Im sure it doesnt matter that its a five speed?
Click to expand...

I wonder why there are 4 wires in that connector. The wiring diagram that I got from the internet only has 2 wires going in. For the brake switch.

Anyway, please let us know if it solved your problem. Come to think of it,
this is probably a switch that is bound to fail in the future. Afterall how many times do we step on the brakes?
 
Nope it didnt work. I too noticed that the part that I took out (factory original) had 4 wires and the part that i installed had 2. After installation I checked my lights and cruise control and they worked fine. However my lights still shorted out about 5 min down the road.

Anybody have any other suggestions? Id appreciate a place to tell the mechanic to look so I dont get nailed with the cost of them doing a complete wiring inspection. Im still too new to the do-it-yourself-mechanic thing to do wiring by myself.

Thanks everybody
 
cplhornby said:
Nope it didnt work. I too noticed that the part that I took out (factory original) had 4 wires and the part that i installed had 2. After installation I checked my lights and cruise control and they worked fine. However my lights still shorted out about 5 min down the road.

Anybody have any other suggestions? Id appreciate a place to tell the mechanic to look so I dont get nailed with the cost of them doing a complete wiring inspection. Im still too new to the do-it-yourself-mechanic thing to do wiring by myself.

Thanks everybody
Click to expand...

What do you mean by 'shorted out'?
- The bulbs are burnt out?
- or the brake light fuses are blown?
- or the bulbs simply don't light up?

Anyway here's the drawing from a MZ5 wiring diagram. I have no idea
if this applies to all mazda5s.

good luck.
 

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  • brakelight.JPG
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I mean that the bulbs just dont work. When I turn on my car they are fine. But after driving for a bit they stop working. I have noticed that I can see when this happens by turning on my cruise control. When my cruise control light turns off on its own, I know that my break lights are no longer working. If I turn off my car and then restart it, they work fine again until they stop working on their own. Im at a complete loss. Very frustrated too.
 
Ok so my brake light are working now which is excellent. However my cruise control still stops working on its own until i shut the car off and turn it back on again.Anybody have any suggestions, or know where to get a 2006 mazda5 wiring diagram?
 
I havent commented here for a while. For some time now, my break lights have been working, however my cruise control is not. Does anybody know what parts I should check, or wiring diagrams in order to narrow down this problem?

Haynes does not have a manual yet, and the Repair Manual from Mazda costs around $150CND. So Id like to be able to work around this if possible.

Thanks everyone!
 
I have seen quite a few vehicles with trailer wiring causing the symptoms you describe. Check for a converter box installed (or if you bought it used - uninstalled) for trailer lighting. Poorly spliced connections, or poorly repaired harness after removing trailer wiring are common. The converter boxes can short out internally causing blown lamps and fuses, and the plugs can short out too. Cruise problems relating to aftermarket wiring of any kind are an easy place to start looking. I have also seen where signal power feeds back through the brake switch causing the cruise to cancel when you turn your signal on.
 
The link is for the CX-9, but if your 5 has their setup, then simply unplug the "T" connector from the left, and right harness (behind the rear interior panels) to completely disable the trailer wiring. That type also has direct power wired to the positive terminal on the battery which should only need a 10mm wrench to remove. Check all your fuses, and test drive it. If everything suddenly works, you have found the problem. A common spot for damage is where the trailer wire runs through the hatch seal - as you close the hatch, the wire breaks, or the insulation gets thin/cracks. Look for a lot of green corrosion inside the trailer plug. If all that looks good, order a new trailer harness.

The type in the picture is a t-style plug and play trailer harness. Not all trailer suppliers stock those, so yours may be spliced directly into your factory tail light wiring. If they are, check the splices carefully.
 
Hi cplhornby, I was wondering if you ever fixed your problem? Our Mazda5 is acting up similarly with brake lights working sporadically (all are out when they're out) and same issue with cruise control not working. I have a mechanic I trust but I would like to at least point him in the right direction when we bring the car in (if I can). Any resolution of your problem?
 
I have an 06 (with auto if that matters) It also has the factory remote start. That system started acting REALLY flaky this winter, like not being able to start or turn off the car with the key. It would act normal using the key fob starter button, but then when getting into the car, putting the key into the ignition or stepping on the brake (which is supposed to turn the motor off) did nothing. THe cruise control didn't work right either, it shut itself off regularly as well. I took it to the dealer who diagnosed it right away as a bad brake light switch, he said it was a fairly common... failure and as soon as the switch was replaced, all was back to normal. THis is the switch on the brake pedal (or maybe the master cylinder, I forgot which) that makes the brake lights come on. Apparently several systems use this switch cycling to turn on/off things, like the cruise or the remote start. Have your brake light switch looked at!
 
Here are my two cents to the original posting of replacing the Brake Switch:

Thanks to the guy who posted the picture! But I misread the way to "turn" to remove. I thought he meant turn up or down. Rather, he meant turn clockwise. Hindsight being 20/20, I now see the arrow means "twist", or "turn", but thought I would comment just in case someone else read it the same way I did.

Also, I could only get 1 hand up in there. I found it easier to first remove the brake switch (I actually broke it out--see above), and then pull out the white electrical connector when the whole unit was hanging down and I could use both hands.

Finally, I bought my brake switch from the dealer, and it was $10 cheaper than the quotes I was receiving from Oreilly and AutoZone. And they had it in stock. You may want to call the dealer first. Total cost...$20, and piece of mind that you got the correct/best part.

Thanks to all who reply on this forum. $100 saved!
 
Thanks mate. Excellent instructions and photo much appreciated. That location is almost impossible to see visually so had to swap the switch by feel. I also noticed that the engine stalling problem I had when starting from a stop has gone away. Evidently the brake light circuitry has some impact on the ECM. Bought the part on Amazon for $15+ shipping https://www.amazon.com/dp/ (commissions earned)

AIMWO4 said:
If you bought it new, it is most likely a relay. The Mazda5 manual can be downloaded if you know how to trouble shoot it yourself. Always check the Mazda3 threads and forums... They have similar issues:

5. Brake Switch Replacement

a. Locate the switch right above the brake pedal as shown.
b. Disconnect the electrical connector by pressing on the release tab;
c. To remove the switch, twist it like an 1/8 of a turn as shown, then pull it out;
brake_switch.jpg


d. Apply reverse procedure to install the new switch.
Click to expand...
 
Last edited:
Hi, I guess the last post was almost 2 years ago, but I recently had same problems (with brake light malfunction and shifter not going down from P position unless you pump the brake pedal several times) on my 5 and it indeed turned out to be the faulty stoplight switch. Thank you AIMWO4 for the picture, it was helpful locating the actual location of the blue switch which is located just above and behind the brake pedal. It was somewhat pain squeezing into the tight small space in an awkward position and it initially took a few tries but once you get the old switch twisted out with 1/8th turn and disconnect the white connector (mine had 4 wires by the way, I think the difference between 2 and 4 is the cruise control. there is a price difference in the parts, too, like a $1 or $2), putting back in the new blue switch and reconnecting the connector was pretty easy. Firestone wanted to charge $105 to diagnose the problem and I am glad I was able to find this post. It looks like it is a somewhat common problem among 3s and 5s. The part is called intermotor stoplight switch and it is made in japan. It was about $21 on sale at advance auto parts. The gentleman who works at the advance auto parts was also helpful and was able to confirm that the problem was the switch by going under the brake pedal and physically press the switch with his finger and when he did, the rear brake lights came on. I hope this helps anyone who might run into a similar problem in the future.
 
cplhornby said:
Nope it didnt work. I too noticed that the part that I took out (factory original) had 4 wires and the part that i installed had 2. After installation I checked my lights and cruise control and they worked fine. However my lights still shorted out about 5 min down the road.

Anybody have any other suggestions? Id appreciate a place to tell the mechanic to look so I dont get nailed with the cost of them doing a complete wiring inspection. Im still too new to the do-it-yourself-mechanic thing to do wiring by myself.

Thanks everybody
Click to expand...

I know you're comment is quite old now... just wondering if you ever fixed the issue? There was a new post (see end of forum) where someone else replaced the switch and mentioned that the four wires switches were for cars with cruise control and the two wire switches are for cars without. Since you replaced a four wire switch with a two wire switch, this may be your cruise control issue.
 
Wishmaster said:
I know you're comment is quite old now... just wondering if you ever fixed the issue? There was a new post (see end of forum) where someone else replaced the switch and mentioned that the four wires switches were for cars with cruise control and the two wire switches are for cars without. Since you replaced a four wire switch with a two wire switch, this may be your cruise control issue.
Click to expand...

I think so, too. Because when I ordered the part from the advance auto parts website, they give you 2 different choices and it says the difference is one with cruise control, and the other without cruise control (although I thought all 5s come with standard cruise control, no?), and when you look at the picture, the switch with cruise control had 4 wire connection and the switch without cruise control only had 2 wire connection. And the gentleman at the parts store also asked me if the car had cruise control or not so I am thinking that must be the reason. Good luck.
 
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