Hello everyone ,

My 2021 CX5's tail lights have stopped working 2 weeks ago - not just tail lights - anything on that circuit ( License plate lights, Tail lights, Front side marker lights, Front parking light - Thanks to 2018 mazda service manual shared here, I know the component names!).

Booked service (diagnosis appointment they say) at dealership A in VIC who kept the vehicle whole day. At 3:30 PM, they said we need car for 2 more days OR you let us work for next 2 hours until 5 PM. Long story short, they could not find what the issue was. Scanned vehicle, no fault codes present. Told me again that the fuse blows (Hurray! which I already told them). Found damage to bumper clips and number plate light (because I scratched it as I inserted screwdriver to take the cover out after watching Youtube DIY video, stopped as soon as I realized its LED and is a sealed unit), hence not covered under warranty. They were going to charge me for 3 hours spent on the vehicle (170 AUD per hour), to which I negotiated and paid 1.5 hour charges. Fault still present, further diagnosis to continue. Vehicle was always serviced at dealership A (Free 1k, 10k, 20k in Mar 2023).

Have now booked another service appointment with dealership B and that's again after 2 weeks. Person has been very helpful over the phone and suggested I disconnect the number plate lights and put the new fuse in to see if that makes any difference. The charges would be 190 AUD per hour if it turns out to be an issue due to outside forces , induced moisture etc (Thought warranty would cover all)

DIY troubleshooting prior to the yesterday's service appointment : Noticed the TAIL 15A fuse is blown. I put in a spare one from fuse box, blows again. I borrowed HORN relay and replaced TNS relay (process of elimination), no difference, fuse still blows. In order to look for a broken wiring / short circuit, took out the tail lights, found spider web behind the left one, cleaned it, installed and no difference. The rear brake lights, indicator lights and reverse lights WORK. I am clueless on what I can do next. Please advise next steps. Also, when new TAIL fuse is used, the lights do come on for a fraction of a second before the fuse blows again.

Vehicle history : 1st year of ownership and the forward sensing camera failed which was replaced by dealership A under warranty. I replaced front grill myself as the baby kangaroo hit it and luckily just damaged the plastic grill. OEM 2021 CX5 grill is 1100 AUD + ~160 AUD OEM rivets , while I got the sport look grill from ebay for 150 AUD + 10 AUD rivets . That was a year ago, no issue since then.

I do not know when the tail light issue actually started, it was only 2 weeks ago when my cousin who was following my car advised that it is all dark from rear until you apply brake, indicate . The only thing I can think of is the 50 km driving we did when it was raining heavily on a freeway, considering its a new car, shouldn't be an issue.

I have attached the tail light circuit wiring diagram for reference.

Thank you !!

 

Unfortunately, just one bad bulb can cause this issue and that generally won't show as a fault on a circuit tester.
It comes down to the "check each one" time consuming ordeal.
Sort of like old Christmas tree lights...

 

And all these lights on this circuit are LEDs, not sure if this makes situation worse or not. I am guessing it would just be a matter of disconnecting connectors at the very end to isolate them.

 

Yeah, I would just use the disconnect on each unit.
Then once you find the "offending member" you check the bulbs.
But even the disconnects will still take time to find/reach each of them.

 

Update: After looking into my security camera footages, I can confirm that the tail lights + others on this circuit indeed failed on the day of long freeway drive (50 km) while it was raining. I can see the front side marker lights are dead afterwards when entering/exiting the garage.

Please advise if anyone has removed 'front combination LED light' on a CX5 2021 (Second generation) before. I tried disconnecting the cable, looks like the one easy to access is the indicator bulb only. I did find another connector on the front combination light however, after disconnecting that, front lights were still working. I think I would have to remove the front bumper in order to access more connectors on the light. I wonder if there is separate connector for LED side marker lights only, since that is only component what I would like to disconnect. My plan is to disconnect both 'front LED combination lights' and put the new TAIL 15A fuse to check if the Front parking light and side marker lights are not the offending members.

Any diagram of new LED - front combination light would be good - 2nd gen CX5

Thanks

 

This might help

 

Thanks @Lobstah for sharing the video, with 2nd gen CX5, the connectors on these LED lights are placed differently.

Update : Finally, got the tail lights and number lights to work. By process of elimination, disconnected main connectors at both of the headlights to isolate them. The tail lights come up. I then plugged in all the connectors on the left headlight, tail light still remains up. However, the fuse blows only when connector for Right front park light + side marker light is plugged in.

So, happy to have no cosmetic side marker light/park light on the front as long as all other much-needed lights are functional.

Got back to dealership A who says since there is tampering on the vehicle, not covered under warranty. I am going ahead with dealership B service appointment who says depending on what they see, would need to lodge a report to Mazda. The person was not sure what the warranty is for the lights.

Any experiences with the dealership when it comes to LED headlights, I hope they don't count them as 'wear and tear / consumables', each light is more than $1k AUD, not cheap

 

If you are within the warranty period of your vehicle, I would think they should cover it (unless there is damage), but warranties are different depending on where in the world you live so who knows. LED lights with bulbs which are not serviceable should not be consumables on a 2021 car. Certainly they are made to last longer than that. The previous gen CX-5's had an issue with premature failure of the LED rings around the headlights and many were replaced under warranty. I have not heard of similar issues with the current gen's lights (2017-2021).

 

I would think that should absolutely be covered under warranty, even in another country. I've seen working taillights on 20+ year old vehicles for crying out loud.

 

They say all is well that ends well

Mazda dealership B replaced faulty front right headlight - told me its roughly $2k AUD but since the car is under warranty, free of charge

Called Mazda dealership A few times, manager refused to talk, staff giving excuses that you would receive call at the close of business, sent email. Kept following up for a week, in last call, mentioned to the staff that I am taking it to social media if I don't hear back today. 30 mins later, email reply arrived saying refunding amount as a gesture of goodwill, money in the bank a week later!

Happy ending!