I have been troubleshooting AC/Heater issues for a while. I took to a Porche/BMW/MB (in that order) garage and they could not figure it out. They tried switching out relay and that did not work, so they put in the old one. That is all they should have done. In doing that, it looks like my thermometer display broke. Has anyone seen this? See image.

It slowly cycles through several characters every several seconds. I am not sure what could have happened. Any ideas?

Attached Thumbnails

 

__________________
Julio Garcia
1987 300 SDL (mine)
2006 Jeep Liberty CRD (mine/kids)
2008 Hyundai Sonata (wife)
2000 Saturn SL AKA "Gocart" (everyone)

There is no relay involved with the outdoor temperature display. There is a sensor that is behind the license plate. It runs up and connects into the display.

It probably need its capacitor(s) replaced. That's typically what fails and you get no visual output.

Thats what I would do first.

__________________
Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k

Looks like the display screen is toast. You'll need a replacement unit.

__________________
1983 123.133 California
- GreaseCar Veg System

2x

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Yup LCD Black Death syndrome.

Time to hit the wrecking yards.

Note that there are 2 versions of the display, a 4-pin, which you probably have in your 1987, and a 5-pin, from 88? and up. If you get a 5-pin be sure to grab the harness connector too. There are several posts out there, including one I did on how to convert it.

http://www.peachparts.com/shopforum/diesel-discussion/348549-outside-temperature-display-question.html

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Actually, I have a few units here. I'd be happy to sell one if you're interested. Might save some time?

__________________
Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k

If you have a spare outside temp display for a '87 300SDL, I'll take one please! PM sent

Hi guys, I am very sorry for the delayed response. I thought I had subscribed to the thread, but did not. I never saw your responses.

Here is the resolution: As most of you suggested, the LCD died on me and I replaced it. The original part number is 1265420227. The part number search points to here: OUTBOARD TEMPERATURE INDICATOR. Fits: Mercedes | Mercedes-Benz of South Atlanta. It does not list the 300SDL, but that is the right part. A different search takes me here, which indicates that the product is no longer available, but gives you the new part number. Either way, you can get it there for a handsome $525 as of this writing.

I got it here for $30 including shipping: Mercedes W126 560SEC 500SEC 350SD Outside Digital Temperature Disp Monitor | eBay

So sorry I did not see your post JamesDean, or I would have pinged you first.

__________________
Julio Garcia
1987 300 SDL (mine)
2006 Jeep Liberty CRD (mine/kids)
2008 Hyundai Sonata (wife)
2000 Saturn SL AKA "Gocart" (everyone)