You are currently viewing our forums as a guest, which gives you limited access to view most discussions and access our other features. By joining our community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join the Ford-Trucks Forums community today!
There are two fuses in the fuse panel under the hood; they are both 7.5? or 75?, amp fuses. the one closest to the front of the truck was blown. What is the blown fuse for?
The fuse positions are #19 (which was blown) and #18 (Which was not blown)
BTW- does anyone have a listing of fusee locations for both under the hood and inthe truck for future reference?
I am abit confused.. the fuses closest to the front of the truck are from left to right #1(7.5A) #2(10A) #20(50A).....#19(20A) is closest to firewall on the left, #18(30A) is just below it...Anyway, thats on my 99. #19 is listed as "Fuel Pump Motor, PCM.
I figured out is was the #1 fuse -trailor tow pakage.
While I was rooting around the panel i found out my truck does not have an A/C diode.
It sits beside the PCM diode, in the under the hood fuse box. I do have air conditioning in the truck if thats what the A/C stands for. Leaves me to believe I am missing that diode. Even if it stood for alt current I should still have one.
#36 is "not used".. #37 (bottom right corner) is your PCM relay diode.. Surprised you don't have A/C.. thought everyone had air on their trucks..In looking at all the fuses in both under the dash and under the hood, don't see any listed for Air Conditioning.
Found it. it is the AC Clutch diode. Its not jumped with a piece of wire is it?
It is on the ground side of the AC clutch solenoid. My guess would be someone wire the solenoid straight to ground bypassing the diode.
there was a wire coming out of the fuse box when i bought the truck, bt it was snipped and never led to anything. I cant remember if the wire was stuck in the A/C diodes place or not. Do I need to get a diode. Im kind of lost still wether i should have on or not.
From the diagram it appears to be there to prevent a back feed of voltage to ground in the event of solenoid failure. Cant really see any other reason for it. If your AC clutch is engaging the solenoid must be getting ground from somewhere
Im kind of lost still wether i should have on or not.
If you are worried about fuse location #36, which is in the front of the box, the second location over from the right, under the hood panel, my owners manual says it is not used. It is empty. Your previous owner must have tap into this location for a accessory.
The A/C clutch will work with or without the diode. The diodes in the batt junction box A/C & PCM are there to protect against any surge which could rarely backfeed through the A/C clutch solenoid and damage any sensitive electronics in the PCM. I would get a replacement for it when you get a chance, but I wouldn't make it a life driving priority. The computer contolled cars and trucks of today are goofy sensitive to any electrical anomolies. Lightning could strike our trucks and 999,999 out of 1,000,000 everything would be fine, but you could discharge a static charge from your fingertip and fry the PCM. Electricity is a strange force. I'm a master electrician, and I don't understand a lot of things I see in a day of service work. Rarely in a 12V direct current electrical system do reverse surges happen, but Ford must have had enough of them happen out of the millions of vehicles they have produced to see it as a cost effective "warranty insurance" policy.
This forum is owned and operated by Internet Brands, Inc., a Delaware corporation. It is not authorized or endorsed by the Ford Motor Company and is not affiliated with the Ford Motor Company or its related companies in any way. FordŽ is a registered trademark of the Ford Motor Company.