mack_psu
Member
- First Name
- Steven
- Joined
- May 21, 2019
- Threads
- 3
- Messages
- 12
- Reaction score
- 3
- Location
- Chantilly, VA
- Vehicle(s)
- 2016 Civic EX-T
- Thread starter
- #1
I just purchased a used 2016 Civic EX-T in late January 2019.
Over winter months I noticed (similar to other threads on this forum) that the rear defroster in this car is not very good.
This week, I borrowed a thermal camera to take some images. I started the engine, and pushed the button for the "side mirrors and rear defroster". The side mirrors get red in the thermal image and are warm to the touch. The rear defroster stays blue on the thermal camera image even after a couple minutes. I can touch the grid lines and they are cold. So I started troubleshooting...
I checked the multi-block fuse (PN 38233-TBA-A01) located inside the engine fuse/relay box. the positions all looked good. I used a multi-meter to check for good continuity from the metal screw post to the bottom metal posts. All were continuous (shorted) so that tells me the fuse is good.
With the engine off, I checked the relay which is called out on parts diagram under control unit (engine room) as item #2 (PN 39792-SDA-A01). it is a four post relay. i checked for resistance between two of the terminals and that looked good. i did not try to actuate the relay by applying 12V to the relay.
Next I used a multi-meter to check the grid lines. they look good and do not have breaks. I checked resistance between a line at the top of the window and a line as low as i good go. I wrapped a piece of aluminum foil over the probes so I had more surface area to touch the wires. the multi-meter read as a short. I think that means that there are no breaks in the window grid.
I turned on the engine again and checked voltage on the grid lines. my ground lead was on the metal rear door strike plate. with the rear defroster OFF, I read zero volts. With the defroster ON, I read 12-14V.
This tells me that the grid lines are getting voltage, but no high current is going across the grid lines.
can anyone help with next step troubleshooting? Are there other relays or fuses in other locations that I need to check?
Over winter months I noticed (similar to other threads on this forum) that the rear defroster in this car is not very good.
This week, I borrowed a thermal camera to take some images. I started the engine, and pushed the button for the "side mirrors and rear defroster". The side mirrors get red in the thermal image and are warm to the touch. The rear defroster stays blue on the thermal camera image even after a couple minutes. I can touch the grid lines and they are cold. So I started troubleshooting...
I checked the multi-block fuse (PN 38233-TBA-A01) located inside the engine fuse/relay box. the positions all looked good. I used a multi-meter to check for good continuity from the metal screw post to the bottom metal posts. All were continuous (shorted) so that tells me the fuse is good.
With the engine off, I checked the relay which is called out on parts diagram under control unit (engine room) as item #2 (PN 39792-SDA-A01). it is a four post relay. i checked for resistance between two of the terminals and that looked good. i did not try to actuate the relay by applying 12V to the relay.
Next I used a multi-meter to check the grid lines. they look good and do not have breaks. I checked resistance between a line at the top of the window and a line as low as i good go. I wrapped a piece of aluminum foil over the probes so I had more surface area to touch the wires. the multi-meter read as a short. I think that means that there are no breaks in the window grid.
I turned on the engine again and checked voltage on the grid lines. my ground lead was on the metal rear door strike plate. with the rear defroster OFF, I read zero volts. With the defroster ON, I read 12-14V.
This tells me that the grid lines are getting voltage, but no high current is going across the grid lines.
can anyone help with next step troubleshooting? Are there other relays or fuses in other locations that I need to check?
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