# Auto compasses **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** cr-v, honda\ **Created:** [June 25, 2010, 6:59pm UTC](https://community.cartalk.com/t/auto-compasses/50855 "2010-06-25T18:59:42Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![nancybgb](https://avatars.discourse-cdn.com/v4/letter/n/ad7895/32.png) [@nancybgb](https://community.cartalk.com/u/nancybgb)\ **Post date:** [June 25, 2010, 6:59pm UTC](https://community.cartalk.com/t/auto-compasses/50855/1 "2010-06-25T18:59:42Z")
Is there an auto compass that works??? (One that actually sticks to something and also tells you your direction…) ---
**Author:** ![ignoramus9](https://avatars.discourse-cdn.com/v4/letter/i/d07c76/32.png) [@ignoramus9](https://community.cartalk.com/u/ignoramus9)\ **Post date:** [June 25, 2010, 7:04pm UTC](https://community.cartalk.com/t/auto-compasses/50855/2 "2010-06-25T19:04:33Z")
the problem is that the coil/igniter, and the radio, and a the heater blower, etc. put out electrical fields that throw the compass off. I do not know how you can shield your compass from these stray signals, but if someone does, short of installing a faraday cage, I for one would like to know. ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [June 25, 2010, 7:52pm UTC](https://community.cartalk.com/t/auto-compasses/50855/3 "2010-06-25T19:52:24Z")
If this is really important to you, get a GPS at Sam’s/Costco/etc. ---
**Author:** ![ignoramus9](https://avatars.discourse-cdn.com/v4/letter/i/d07c76/32.png) [@ignoramus9](https://community.cartalk.com/u/ignoramus9)\ **Post date:** [June 25, 2010, 7:55pm UTC](https://community.cartalk.com/t/auto-compasses/50855/4 "2010-06-25T19:55:32Z")
consder the relative cost, faraday cage vs. tom tom. ---
**Author:** ![ken\_green](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/ken_green/32/816_2.png) [@ken\_green](https://community.cartalk.com/u/ken_green)\ **Post date:** [June 25, 2010, 8:08pm UTC](https://community.cartalk.com/t/auto-compasses/50855/5 "2010-06-25T20:08:32Z")
Compasses’ magnetic north needs calibrated by geographic region. Your accuracy can be ruined just driving accross the country, until you return home. An owner’s manual has instructions for regional calibration. ---
**Author:** ![Whitey](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/whitey/32/24680_2.png) [@Whitey](https://community.cartalk.com/u/Whitey)\ **Post date:** [June 25, 2010, 8:26pm UTC](https://community.cartalk.com/t/auto-compasses/50855/6 "2010-06-25T20:26:51Z")
No, no normal compass will probably work. There are too many magnetic fields nearby in a vehicle. Personally, I think if you need a compass to know in which direction you are heading, you probably need a GPS anyway. ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [June 25, 2010, 9:00pm UTC](https://community.cartalk.com/t/auto-compasses/50855/7 "2010-06-25T21:00:07Z")
GPS is the only way to go. Besides the magnetic fields and the iron structures in your car, both of which affect a magnetic compass, everything around you including steel framed buildings, iron deposits, scrapyards, etc all contribute to the inaccuracy. Even our B52 bombers back in the early '70s could only get an estimation from the magnetic flux valve. Magnetic variation and magnetic deviation (irregularities in the earth’s flux lines) needed to then be calculated in. ---
**Author:** ![tardis](https://avatars.discourse-cdn.com/v4/letter/t/f0a364/32.png) [@tardis](https://community.cartalk.com/u/tardis)\ **Post date:** [June 25, 2010, 9:59pm UTC](https://community.cartalk.com/t/auto-compasses/50855/8 "2010-06-25T21:59:57Z")
Funny, the compasses in the last four cars that I’ve had worked perfectly fine. They were built into the rear view mirror. (My prior cars didn’t have compasses.)