Electrical problem - seat belt wanring bleeper controlling electric windows

[petemillis]

I\'m stumped on this. 3rd gen RX7 sold to a guy two or three months back. Summer, nice and dry. Just after selling, it developed a weird fault. For the first hour after starting up the seat belt warning light and sounder would continunally go, and when you operate the electric windows they go up or down in time to the bleeper. Like bleeper and warning light on, electric window moves a couple of inches, then stops when the bleepr and warning light go off. After an hour it would clear up and all be fine.
We first of all put it down to maybe the battery being knackered and taking too much power until it had been charged up enough. New battery in, still does this weird thing.
So I checked the alternater - perfect, nothing wrong, spot on stead voltage.
So tonight I checked the earthing of the engine and the battery to the vehicle. Again perfect, and next to no resitance between engine and car body (maybe 1 or 2  ohms but I don\'t think that counts!).
The problem is worse than it was when it first happened. Initially it was an occasional thing. No it\'s constant and doesn\'t even clear up after a couple of hours.
It\'s almost as if the electric windows are wired in to the seat belt warning indicator. The only electrical work that\'s been done is to swap over the stereo (we haven\'t got round to doing the speedo chip yet and I now want to get this gemlin sorted first). This was happening BEFORE the stereo was swapped.
Please please ANY ideas? I\'m pulling my hair out now.
Cheers
Pete

[sdminus]

First of all mate you should not have a resistance of 1 or 2 ohms. the whole ring main circuit is less than this and it can cover up to 100  m. it should be low to no milli ohms. there are some electrical schematics on i luv my rx7 . remember these are schematics tho.
scott

[petemillis]

Cheers for that. It is milli ohms now I look at the meter again. I had it on the 200 ohm range and it reads .2 if I touch the probes together, and the same if I touch them from the engine to a screw on the car body, so I assume the resistance is negligible.
I\'ll check out those schematic. Looks like I\'m heading for total headfack tonight. Maybe I\'ll just crack open the beers instead..

[leggysrx7]

hi Pete.

I have the same problem..folk reckon its a dodgy earth somewhere, but i havent had a chance to look..it\'s very,very annoying...happened after i changed the stereo..so i reckon while getting rid of the spagetti junction of wires i\'ve done something i shouldn\'t have...

...if you get it sorted will you please,please,please let me know...it\'s driving me insane!!!

Marc

[sdminus]

Cars are hidious for bad earths and parellel return paths. ie if a earth breaks down it can and will track through another device to earth activating it.
scott

[petemillis]

Looks like the solution to this problem is here
http://www.mazdarotaryclub.com/forums/showthread.php?s=&postid=85102#post85102
I\'ll post if it works (or if it doesn\'t!).