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Thermal Fuse Part Identification Help

Gordon Lehman

Mar 8, 2018
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Mar 8, 2018
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I am trying to repair an Airbag control module and it appears the thermal fuse has gone bad.
These units are from an early 1990 Mazda/Ford car.
It appears they used two types of thermal fuses used in these modules.
They are really interchangeable and are the same size and are held in place with four solder joints.
The first has an exposed thermal fuse wrapped by a center heating element.
No Name Thermal Fuse.jpg

The second design is not as clear since it is covered with a plastic cover.

Micro Devices Thermal Fuse.jpg

It looks like it was made by Micro Devices with model Number 4AH02002?? and E7TF-I4A09??

I found the thermal fuse part number for the exposed fuse, but it is nearly impossible to extract the fuse and retain the heater element. I would very much like to find the Micro Devices Thermal fuse since then I could just replace the whole component on the board.

Thank you for any help.
 

Harald Kapp

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Nov 17, 2011
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I recommend you do not mess with an airbag/airbag control module. It may blow in your face while fiddling around with it or it may not blow at all when required.
If the thermal fuse has gone bad, you never know what else may have suffered. And you have only once to test it ;)
 

Gordon Lehman

Mar 8, 2018
2
Joined
Mar 8, 2018
Messages
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Harald,

I understand your concern, and if I had other options I would not mess with this, but these modules are no longer available as new, the only way to keep our cars airbags functioning is to replace this thermal fuse.

As I wrote, these fuses seem to have aged out, because when the heating element kicks on the fuse is melted, and as you can see in both of these the fuse looks fine.

So, if anyone has any ideas on where to find these Micro Devices Thermal Fuse/Heating Element component, or an equivalent. The exposed thermal fuse is a model NTE-8139 - 141degC 15-amp.
 
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