Rear inner taillights do not work

Tiny
WALLY AB
  • MEMBER
  • 2015 MAZDA 5
  • 2.5L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 138,000 MILES
Checked fuse, all lights work at the back except for the idle light on the hatch. Checked bulbs and power going to sockets and there is none. Checked ground on the hatch and it is fine. Baffled.

Could not find a wiring diagram online for this issue. What should I check next?
Saturday, August 10th, 2019 AT 7:45 PM

5 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Hi,

If you don't have power at either of the bulbs and your ground is good then you just need to trace the wiring backwards until you have power. The attached wiring diagrams shows that the same feed wire for the tail lights is used for the license plate bulbs. Are they working? If not, then you can jump to an inline connector C-04. If they do work then I would suspect the splice that splits the feed from the single blue/black wire to where it brings in the license plate bulbs. Unfortunately, there is no location for this splice so you will need to trace the wiring but I assume it will be close the the rear of the vehicle.

Let know what you find. Thanks
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Sunday, August 11th, 2019 AT 10:23 AM
Tiny
WALLY AB
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Thank you for your response. The license plate lights work, and reverse lights work as well. Only thing is the two inner taillight bulbs don't have any power.
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Sunday, August 11th, 2019 AT 6:38 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Okay. Then trace the blue black wire from both bulbs and find where they come together. There should be a splice. Make sure that is okay. Then start following that wire up through the vehicle and find where you have power. Then repair the damage and you should restore the power. If the plate lights work, then you have power somewhere on that circuit because they use the same feed wire.

Also, did these just stop working or did you just buy the vehicle? I am wondering if someone else was in there and we have to think about what someone else may have done.

Lastly, I just want to make sure we are on the same bulb. What is the color of the wire coming from the bulb that you have no power on?
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Sunday, August 11th, 2019 AT 7:06 PM
Tiny
WALLY AB
  • MEMBER
  • 97 POSTS
Bought the car last week, it wasn't working then nor now. The bulb that has no power is blue and black. We tested it at connector connecting the harness from the car to the hatch, so it is an issue from inside the car.
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Sunday, August 11th, 2019 AT 8:28 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Okay. That is great. I am sure you will find power if you go back to the splice where the plate lamps come in. However, I would just go back on that circuit until you find power and then just run my own wires to each bulb. I am sure you have a rub through or an issue at the splice but if you have no power there, then just do whatever is needed to run power on that circuit back to the bulbs. Even if you have to directly to the fuse box in the engine bay and just run a wire to the back of the vehicle.
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Monday, August 12th, 2019 AT 5:16 PM

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