OK, I went crazy for the last week on the web searching for the location of my 1997 econoline air bag module. I found every other vehicle ever manufactured including many F 150's but the web is silent on the location of this module on the 1997 (through 2003ish). I went to the wreaking yard and seem to remember seeing one behind the drivers door on the body of a cargo van. I started pulling my conversion van apart but after searching found no trace. Until today when I found it! So I hope this helps others who may need to address this item. It is located up under the dash on the passenger side outer bulkhead - forward of the passenger door under the dash. When I bought my van it did the five sets of five chime which I finally discovered was the alarm code for a burnt out bulb on the airbag instrument light. I pulled the instrument panel out replaced the bulb and it flashed another fault code! OK so 1 flash then pause then 5 flashes then repeat and then go to steady on. So The module sensed an intermittent short and sent a signal to cook the thermal fuse! Sigh. So I found a way to replace the thermal fuse and found a couple messed up wires under the drivers seat that appear to be part of the driver restraint system. I will research and see if this might have faulted the module and hopefully be able to get the situation corrected without having to purchase a new module or pay Ford to trace down an "intermittent" short, which is the kind I truly hate because they seem to always behave while you are trying to wring them out.
Cheers!

 

I believe the under-seat wiring you mention is mostly a seat belt not buckled warning feature. At some point the SRS was upgraded to include lap belt pre-tensioners where that wiring became far more important, any faults in those devices or interconnecting wiring would set the flashing fault codes of the SRS dash light.

I've never known a sensed intermittent wiring short to intentionally cause a fuse to overload but that's something maybe useful for anyone else having this sort of problem.

Glad you got it solved.

 

Thank you JWA, The seat belt warning function works fine, however the system appears to include the "lap belt pre- tensioners" with the associated hydraulic (pyrotechnic?) tube, at least for the driver seat. I need to research this carefully as I understand that any accidental deployment can have deadly consequences. I only just recently discovered what the system was. apparently when the module detects a short it will send a signal to heat the resistor associated with the thermal fuse to blow it. This cuts off ALL power to the air bag system to prevent accidental discharge. The fuse is supposed to NOT be serviceable and is supposed to require replacing the whole module. There is however this video that displays how to change out the fuse in the module. I am just waiting for my thermal fuses to arrive. Thanks again.

 

Any info you can share about this, photos of your repairs or links to helpful sites might make a good addition to our general knowledge base here, perhaps including it in our tech folder?

I've never dug too deeply into the SRS apart from knowing basically how to disable it when working around or with any of its components. So far I've never had one accidently trigger and deploy---that's a good thing.

FWIW due my own negligence my driver's seat belt pre-tensioner wiring was crushed, the warning light always on. During first key-on the code would flash, took me about a year before I was tired of that light and the flashing before I determined what was at fault. A simple wiring repair job, carefully re-energizing the chassis and all was well. Of course first time ignition was turned on I was NOT in front of any of the air bags.

Thanks for your input---learn something new every day.

 

I would be happy to "pay it forward" any way I can for all the great help I have found on this site. I will take pictures and include appropriate links for anyone experiencing this issue. Thank you for your advise as well JWA..I am just waiting on the thermo fuses to arrive before I tackle it, in the mean time here is some information I came across that might be a a leg up for anyone who is looking at doing this..

 

Thank ya Sir----I'll be watching this thread to see anything new you post. Regarding the video its nicely done but to my mind not the best tutorial or "how to" for this operation. With the various IC's I'd like to see an anti-static wrist band and a bit more time discussing how to solder/desolder components to a PCB. Automotive PCB's are notoriously thin and cheap, too easy to muck one up without realizing it. Honestly for $55 at a salvage yard and even though I'm fairly skilled working with electronic devices that's a small cost for what is a lot of work.

Even though this is something rarely discussed here its still one of those things we should know or at least keep in mind. The cost of any SRS component of the pyrotechnic variety ain't cheap.

None the less great contribution, very much appreciated!

Reps sent BTW!

 

Ok, The thermal fuses finally arrived and so I was off to the races!!
I did some research...(QVM Bulletin No. Q-49) which was a bit..sobering
But I pulled both the battery cables and waited for not 30 minutes, not an hour, my neighbour came over to see what I was doing and we talked for a couple hours. So I was reasonably certain the circuit was dead and I pulled the module. Only 3 screws and a wire connector, so a piece of cake! - "Donkey Poo Cake" !! The screws you have to contort and remove by feel (about 45 minutes worth...yeah I am old and need some Ben Gay now) but I got em and that goes for your little connector too! So, I take the module to the work bench and remove the 4 torx T20 screws, then use a razor knife and a 5 way to remove the RTV sealant. Then I pull and pry the thing apart and discovered why I can find nothing on changing the fuses in these modules ... The system is totally different from the one I linked the video to and the thermofuse housing (if, indeed that's what it is) Is MUCH smaller than the ones in the video and may be smaller than the thermal fuses I have purchased. The pins and solder on the back of the board are miniscule. I think that some folks might manage to get them desoldered a very few might be able to solder a new component in but I know for sure my skills do not approach this level. I am thinking of Clint Eastwood when I say "A man's gotta know his limits" and its time for me to obtain another module. I like doing things myself and take a great deal of satisfaction when I do the research and make the fix. I am still not to old to learn something new but this one I am going to forgo (especially when I find I can get a module in the $40.00 range!!) So I will solder up the two broken wires to the drivers seat pre tensioner, secure the harness in a safe location and install another module, cross my fingers , count to three and reconnect the battery As long as no airbags deploy and the pyrotechnic pretensioners don't fire off I will call it a fine well done job! In the event of a sudden deployment or discharge I will just tell the Insurance company it was vandals who broke in and just look what they did! Hooligans!
(...Not really)
I will see if I can post some pictures of my folly..

 

I wish I had a dollar for everything I have fixed after ignoring this warning.



DANGER, Will Robinson!

Great write-up, Z, and excellent photos.
jim

 

P'shaw---I always viewed those warnings as a challenge, one not to let pass by without seeing how well I could prove it wrong!

I'm of the same camp though, love to dig into something just because---sometimes to great effect, others having to buy another part or whatsit. Add in I've been soldering electronic parts into amplifiers etc since the 60's but once PCB's came into vogue I never took the time to learn now NOT to burn those up.

You're not out too much, it was a good and probably fun exercise in futility plus you've got a great story now---I count that as a win!

 

I always liked the "could malfunction" part. If it were not broke, I wouldn't be messing with it! haha

I also am guilty of still taking the old one apart after replacing it, just gotta know what's inside. The soldering aspect of it has gone from American Beauty 100 watt irons to solder ***** and industrial heat guns for surface mount technology. All that was driven by robot built stuff so fixing it is a challenge in today's throw-it-away world. jim

 

Yes JWA, that's my read as well. The upshot is if I could not repair it, the old module was toast anyway, so no real loss..even in the event of a "meteor shower" or "alien approaching" ..but now I know what is inside and anyone who has this issue can do a little research and find something on the subject (my post)..which is something I did not have. I was able to purchase another module on ebay for $35.00 so...yay for me! Now as the old module was flashing the 51 fault code (= fried thermo fuse = no power to system) does anyone know if I can run the van without a module plugged in (and without dire consequences) until the e-bay module arrives..? and thank you all for input

 

Apart from the annoying dash light there shouldn't be any issues running without the module. Of course there's absolutely no SRS now, a problem only if you're accident prone and carry at least one passenger in the right seat.

I'd be curious to know what DTC is triggered by the module missing, the same as it having failed in service?

When the eBay module arrives you can disconnect just the negative battery cable although that's not a huge time saver. Because there is no module present now there's no real fear of triggering the SRS due stored energy in an existing module.

Still once installed and time to re-connect the battery do so without anyone inside the van----just to be safe.

BTW thanks for all this Zardoz----it has been interesting so far!

 

I am suspecting I will get the same code I did before (51) which is what started me on this journey in the first place. I will let you know when I get it back together (good safety tips and thank you!). When I bought the van there were many systems that were not "online" or missing components.I am happy to say to the best of my knowledge the SRS will be the last item on my punch list to bring back online. Then a little upholstery and some minor body work and Viola! she will be done and ready for the prom! I am going to get out my steam cleaner and do the carpet later today. I will post some pictures of my front seat pretensioner wiring repair... They are soldered (normally a tighter wrap but little space and oversize monkey hands)...shrink wrapped...taped for good measure (Scotch #33)....and taped again for extra good measure with the wiring re-routed to avoid any future strain on the bundle...thanks again all...

 

ok..suspense is over the airbag light comes on and stays steady..no code..(no module = no code....) ...when my module arrives I will plug it in and I will have a SRS system and be good to go......

 

Repair looks good enough for the use and location----keeping those sorts of wires attached to something solid is a wise idea.

If you were as **** as I am about creating or repairing factory wiring harnesses I could drown you with info and products to do just that.