Rear Defogger help
Thread Starter
Teching In
Joined: Sep 2005
Posts: 20
Likes: 0
From: Clermont, Fl
Rear Defogger help I just got my 02 ss the other day and the rear defogger wasnt working like it was supposed to. After a quick search i found the issue with the circuit breaker. After replacing the circuit breaker the defogger stays on a little longer, but not nearly long enough to defog the window.
So i got my meter out and checked all the circuits. The defogger has .7 ohm across measured at the 2 terminals. The ground circuit has .3 ohm resistance, as does the power feed from the cricuit breaker to the control head and the control head to the defogger.
Then i checked for any voltage drops across all the circuits. I found 12.5v going into the control head, but only 10v coming out. No voltage drops anywhere else.
So the point of this post is if anyone has a properly working defogger and a meter, could you measure the voltage at the defogger power supply (purple wire) and let me know what you are getting. im getting 9.9v. Just wondering if this is normal.
Thanks.
So i got my meter out and checked all the circuits. The defogger has .7 ohm across measured at the 2 terminals. The ground circuit has .3 ohm resistance, as does the power feed from the cricuit breaker to the control head and the control head to the defogger.
Then i checked for any voltage drops across all the circuits. I found 12.5v going into the control head, but only 10v coming out. No voltage drops anywhere else.
So the point of this post is if anyone has a properly working defogger and a meter, could you measure the voltage at the defogger power supply (purple wire) and let me know what you are getting. im getting 9.9v. Just wondering if this is normal.
Thanks.
Joined: Nov 2003
Posts: 11,328
Likes: 345
From: Jacksonville, FL (originally from Toronto Canada)
Did you replace the circuit breaker with another breaker or a fuse? Several people have reported that even new circuit breakers still shut off too soon. A 30-amp fuse won't have that problem.
Also, when you say it's not on long enough, how long is that? It is designed to stay on only 10 minutes.
Also, when you say it's not on long enough, how long is that? It is designed to stay on only 10 minutes.
Thread Starter
Teching In
Joined: Sep 2005
Posts: 20
Likes: 0
From: Clermont, Fl
Did you replace the circuit breaker with another breaker or a fuse? Several people have reported that even new circuit breakers still shut off too soon. A 30-amp fuse won't have that problem.
Also, when you say it's not on long enough, how long is that? It is designed to stay on only 10 minutes.
Also, when you say it's not on long enough, how long is that? It is designed to stay on only 10 minutes.
It stays on for 2 maybe 3 min if im lucky. before it only stayed on for about 30 sec.
Joined: Nov 2003
Posts: 11,328
Likes: 345
From: Jacksonville, FL (originally from Toronto Canada)
No need to worry about using a fuse. The only difference (in theory) between a 30-amp fuse and a 30-amp circuit breaker is that the fuse has to be replaced when it blows - a circuit breaker resets after it trips. The reason I say "in theory" is that many circuit breakers don't live up to their rating - they heat up and trip when they shouldn't.
The defogger circuit will normally shut off based on the timer built in to the switch. The problem is caused by the circuit breaker overheating and tripping before the timer can finish. A 30-amp fuse won't blow unless the current exceeds the rating so it will allow the timer to do its job. It still protects you against situations where the current might exceed the 30-amp limit.
The defogger circuit will normally shut off based on the timer built in to the switch. The problem is caused by the circuit breaker overheating and tripping before the timer can finish. A 30-amp fuse won't blow unless the current exceeds the rating so it will allow the timer to do its job. It still protects you against situations where the current might exceed the 30-amp limit.
