air bag light comes on at strange times

meamjw · Feb 20, 2019

My niece has a 2004 Mazda Tribute with a strange air bag light problem. She can make a 40 mile round trip without the light coming on if there are no high load devices on, but if she turns on the heater or lights the air bag light comes on a few seconds later. To me this means the problem is due to reduced voltage but I have no experience with Mazda and I live 600 miles from her so cannot do any hands on diagnostics. Any suggestions would be greatly appreciated.

telectrix · Feb 20, 2019

take the bulb out ???.

Shoei · Feb 20, 2019

Could be a dodgy alternator, maybe just a slipping drive belt. Could send her one of these to check it out.

ruston · Feb 20, 2019

It might also be the seatbelt pretensioner if anything is tucked under the seat and affecting the tension.

PEG · Feb 21, 2019

It could be many things,but a start,would be a basic code read,with codes listed,cleared,and then initiate the fault by the actions mentioned,and then read again.

If it is reliably coming on,with the accessories mentioned,and,clearing on re-start,it does sound like an earthing issue,or a fault with the control ECU. It also could a spurious fault,such as a deliberate or damage related bridging of wiring....had a radio fitted? any other electrical problems?

It warrants investigation,as here,it is an MOT failure,and although rare,a fault prompting the deploying of the air-bag, during normal driving...is not conducive to road safety