Hey guys - I thought i’d share a little winter project I worked on over the holidays, a retrofit blind spot monitor kit. The 981 does a lot of things very well, but the blind spot when the top is up is one thing that I’ve struggled with. Since I first started driving, I was taught to set my mirrors to show my blind spots (and not look straight down the car) but at 7am driving 40 mins to work, a little help would be nice to alert me if someone’s actually in my blind spot. Since the 981 uses the same door cards as the 718 and 991.2, which offered a blind spot monitor option, I figured I could retrofit the OEM indicator lights with an aftermarket system, giving the system an OEM look and feel.



I’ve seen the Usa Spec BSM200 kit on other cars, and have heard positive results, so I thought that would be a good place to start. A discounted “new in box” kit popped up on ebay, so I rolled the dice. I ordered the BSM Porsche indicators from a dealer, which were about $70 a piece or so, and got to work.



The rear radar (monitors) get installed behind the rear bumper cover, and the kit comes with a tool to align the rear sensors properly. This took some finessing, and my craftsmanship won’t win any awards, but I’m confident they will hold up in place for years to come. From there, you run the cables from the sensors to the brain, through the convertible top and rear carpet, tie into a reverse signal, turn signals, and your 12v ignition and ground, and you are good to go. The kit does use an OBD2 plugged in cable, I’m assuming for speed monitor, as the kit doesn’t work under 6 mph. The kit also becomes more sensitive and has a further reach if you are in reverse, just FYI. I thought about skipping this part, but I already have a reverse signal input easily available from my joyeauto rear camera retrofit, so was easy to tap into. (you can tap into a line under the drivers seat for the rear BCM if you needed another reverse trigger… the front turn signal triggers are up in the front BCM, black with white stripe and green with black).



If you were going to just use the provided BSM 200’s light indicators, I probably would’ve just run them up the sides of the dash, and double sided taped them to the A-pillars…which would save you the hardest part of the install imho. To run the cable through the doors properly, you need to first remove the door panels, then remove two plugs on the inside of the cabin, then push the plastic tubing out of two cavities, and disconnect the plastic tubing. I ran a metal coat hanger through it (which was a pita) then taped the cable to one end, and fished it through. Yes, this part sucks, and yes my hands hurt for days after doing this. From there, I couldn’t find a great place to run the cable from inside the door membrane to the outside (while still inside the main door panel), so I drilled a small hole, fished the cable through (so it was out of the way from the window going up and down), then siliconed it in place. I first tried to use an existing hole, but once the window went down it sliced it in half so… lesson learned. Once the wires were ran, I tested the system with the provided LED’s, and the system worked. Next, was figuring out how to retrofit the OEM triangle pieces. In a perfect world, I’d love to find a used door card wiring harness from a 991.2 or 718 so I could use the oem plug and just wire it in…but since I didn’t have that, I have to make my own two plugs (from an old steering wheel harness), and heat shrinked around the plugs just in case. Next, I had to carefully slide the plugs into their pins and prayed they stayed. They bit a little, and after 4 weeks of use, they haven’t come undone so I think we are safe. I’ll just say that if I have to remove the door cards for anything else in the future, this will be my least favorite part. Does anyone have any leads on where to find a plug that would clip into the OEM indicator that I could retrofit?



The system lights up upon startup, and behaves how you think an OEM system would work. If there is someone in your blind spot, the indicator lights illuminate, and if you put your turn signal on while someone is there, the light flashes, and included buzzer goes off simultaneously. I’ve got my buzzer down by the kick / fuse panel, and if I’m jamming to some tunes or have the top down, it probably won’t cut through the music, but I’m happy with how loud (or isn’t loud) the unit is. For my purposes of the car (half awake at 7am), the lights / system really does the job I need it to do, and I rarely am using my turn signal when someone is right there on the highway next to me…but I had to test it out to make sure it works…so there’s my feedback. I haven’t experienced any false warnings, and I’m 10/10 happy with the performance of the system.



Lastly, the oem BSM system would typically be controlled by the canbus / dash for brightness (low / medium / bright). . Since I can’t do that, the oem lights were BRIGHT AS HELL and needed to be dimmed down. I tried an LED dimmer, which seemed to work well on the brightness, and provide a slow soft glow up to the brightness level, but the trigger signal was a full second delayed, and that would just be my luck that it’s delayed when I actually need it…so I returned the LED dimmers and just decided to run some window tint over the entire triangle oem indicator. They are glossier and not as ‘clean’ looking, but the tint amount is PERFECT and doesn’t blind you when the lights come on, but are bright enough for you to see and recognize someone is in your blind spots.

 

I just drive faster than everybody else.

 

beatifiul job but it looks like a lot of work

 

thanks - yeah a few nights work in the winter I won't miss...