DART Tag windscreen issues - current model 3 series?

[JCW]

Hi, has anyone experience problems with the DART tag or similar electronic toll tags not working on a 3 series as I've recently changed my tag to no avail, and had the same problems in France with the Sanef version; strangely this wouldn't open the barrier but did charge to my account so am wondering if this is a similar issue to that affecting older Renault models with heated screens.

[E30M3SE]

Has your bmw got a comfort front screen?

[JCW]

Yes, but other vehicles have had it with no issues. Tried searching online but can't see any reported issues so are you suggesting this is the cause of it?

[E30M3SE]

Yes, the coating on the comfort screen hinders the signal from traveling through, had a major issue about 8 years ago with a internal 'taxdisk'type car kit antenna in a Renault, which was absolutely useless for signal until an exteranl aerial was fitted.

[Slurms]

Isn't there normally a gap (often behind the rear view mirror) to allow signals through?

[Glassman]

Slurms said:

Isn't there normally a gap (often behind the rear view mirror) to allow signals through?

Some of the French cars had a small rectangle at the bottom of the screen to allow signals to pass through; other cars will have an area above, or around the mirror assembly which doesn't have the solar coating (usually disguised with a dotted silk print).

But if the OP's 3 has a rain sensor, there may only be a gap of about 5-10mm where the solar coating meets the black edge.