Heated windshield question..

[BimmerFlyer]

Hi guys, Pete here,
Winter has arrived here in NW Ohio, and I noticed that my heated windshield under the wipers is not heating up, and neither are the heated sprayer nozzles, at least they don’t feel warm..

A look at the electical diagrams and the manual says that should come on on their own below 43 degree F..and are wired in parallel thru the k198 relay behind the glovebox... relay controll power is thru fuse 20 and 30 in the engine bay fuse box, and they are both good..

First question is, are their commen problems with these systems? i will see if I can pull the A pillar cover of and see if I get power at the window, but anything else?

Second Question is, I cant seem to figure out what fuse feeds the power to the relay, anyone know? Electrical scematics and chasing electrons are not my strong suit..

The mirror heat works like it is supposed to, So I presume that whatever generates the signal for these systems INKA ? Works normal..
Thanks
Pete

[psjr]

The power that goes through the relay to the windshield heater and the nozzles is fuse 30, which you have already checked. Fuse 20 is the relay switching line which is grounded by the IHKA.
Probably not uncommon for someone to forget to plug the heater in after replacing the windshield, but that wouldn't explain the nozzles not working either.
The mirror heating is actually controlled separately - it is controlled by the GM, which gets the outside temperature signal from the IKE. So that doesn't rule out the signalling being an issue.

[TheAngryBear]

TIS actually says it switches off at 43°F and on at 37°F. So it has to be 37°F or below to come on and then doesn’t turn off until 43°F or accessories off. so to validate power there you may need to put ice on the temp sensor or wait for ambient temps to be 6 o C or terminal 15 OFF


2001 750iL DD74441
Stock

RIP: 2003 540iA Sport GS56111
H&R front springs, Ultimate Cup Holder, Euro Dash & Armrest, Grom, BavSound Stage1

[BimmerFlyer]

The power that goes through the relay to the windshield heater and the nozzles is fuse 30, which you have already checked. Fuse 20 is the relay switching line which is grounded by the IHKA.
Probably not uncommon for someone to forget to plug the heater in after replacing the windshield, but that wouldn't explain the nozzles not working either.
The mirror heating is actually controlled separately - it is controlled by the GM, which gets the outside temperature signal from the IKE. So that doesn't rule out the signalling being an issue.

Thanks for the response, I will do some more probing today... That is how I read the scematic as well, just thought it was a little strange that the power feed for that whole windshield area and the washers was only a 10 amp fuse, that why I thought I was missing something...
Am I correct in assuming that, as long as the dashboard temp(IHKA) is below 37, I should have window and Nozzle heat?, or at least a signal to the relay? So pin 85 on the relay holder should be 12v below 37F ?
Thanks for the help..
Pete

- - - Updated - - -

TIS actually says it switches off at 43°F and on at 37°F. So it has to be 37°F or below to come on and then doesn’t turn off until 43°F or accessories off. so to validate power there you may need to put ice on the temp sensor or wait for ambient temps to be 6 o C or terminal 15 OFF


2001 750iL DD74441
Stock

RIP: 2003 540iA Sport GS56111
H&R front springs, Ultimate Cup Holder, Euro Dash & Armrest, Grom, BavSound Stage1

Thanks for the response, yeah, I misquoted that... on at 37F, off at 43F.. good news it is 20F this morning here in NW Ohio, so should be able to test it...
For those that have this working correctly, I presume the window and nozzles become warm to the touch? I know the mirrors feel nice and toasty and imagine that the window would feel similar?
Thanks
Pete

[BimmerFlyer]

Did some trouble shooting today ( in the cold).... I have 12V at both the windschield connector and the hood connector for the sprayers, so the relay and triggering signal are good.... Ohm’ed out the sprayers and they both come in at about 50, so I presume maybe that they must just not get hot enoughto feel much heat on top of the hood...

The window came back as “open” , so I have a broken wire somewhere, either in the window or on the power lead, but there is not much room under the dashboard, so hard to see ....will do some more looking.....
Pete

[Qsilver7]

Just some FYI about the heated windshield base, heated washer jets, and heated side mirror cycle (if they haven't burnt out )...for those that didnt know:

[BimmerFlyer]

Thanks Q, I have seen that schematic for the nozzle/windshield heat before, I did not know the mirror duty cycle......good to know....
I will see if I can get a better look at the windshield wiring, see if I can see if the leads are damaged, or it is in the actual window itself..... need to see as well if I can get the nozzles out and see if they warm up...
thanks for the info.
Pete