2000 B3000 Mazda Windshield wipers will only work on high speed (not on low speed or intermittant ) and radio stays on with key out of ignition. This was happening before but only on very rainy days so I could live with it. It happened today on a perfectly clear day after I washed my truck at a car wash (wand type car wash). I had trouble getting the key to turn in the ignition switch once but it has been fine since, This makes me suspect it though. Could it be my turn signal/wiper on off switch also? The ignition switch is kind of loose - some play in it. thanks as usual

 

Hook up your ELM scan tool & running FORScan diagnostic freeware discussed here, https://www.ford-trucks.com/forums/1...-scantool.html, that's tweaked for Ford/Mazda, as this combo can query all of the vehicle computer/controllers, including the GEM/body controllers for trouble code clues that could help focus your trouble shoot. Post All trouble code Numbers.

 

I would look for a bad ground, such as the bare wire ones that are bolted to the rear of the block or head, and then connect to the cab.
You are experiencing loss of ground when things get wet, I think. When you lose a normal ground, the path for electrons may go through other things, such as the radio. Even stepping on the brake pedal can enable 'other' things to work as the brake light power goes 'backwards' through the cab... or ??? depending on which ground is missing or temperamental.
I do not suspect you would get any codes, but certainly could be mistaken.
tom

 

Thanks pawpaw for quick response but I don't have a scan tool and need another way to troubleshoot. Problem has cleared up again since the car wash but it took overnight to do so. Thanks tomw for your input but I don't understand how water can affect a ground connection, I will check them though. I checked the wiper/radio problem about 4 or 5 hours after washing my truck and it was still a problem. Like I said it took overnight to clear up. Sorry I didn't reply sooner but I am having computer problems as usual. Could dampness/water affect a relay. How could wipers/radio be connected electrically other than a ground connection? thanks once again

 

The inexpensive ELM & running freeware FORScan on your choice of viewing device might be able to simplify, focus & thus shorten your trouble shoot, so give it some serious consideration for your Electronic Toolbox!!!

I like tomw's faulty ground/ground loop idea. The ELM scan tool can query the GEM module that controls the wiper timing function, for more trouble code clues that might more tightly focus the trouble shoot.

If your not comfortable using a scan tool, then have a look here BBB Industries- Premium Alternators, Starters, Power Steering Products | TSB's & Wiring Diagrams for wiring pictorial diagrams that you might find useful in using your multimeter to perform voltage drop & continuity tests & to look up items that use common ground points.
Another thought crossed my mind, the Ranger is known to develop a water leak at the lower passenger side base of the windshield, that'll drip onto the ECM, that's located above the glove box, so check for water leak signs there.

More thoughts for consideration, let us know how your trouble shoot goes..

 

Water can act as an 'electrolyte' or a conductor when it is combined with salt or other chemicals. You get a wet truck, and water can flow around open ground terminals that are held to the cab sheet metal with screws and toothed washers. If loose, the conduction is poor, add some water, and the conduction increases. That is why rust works.. there's conduction by salted water or just water & dirt that allows electrolysis. Or an oxidation/reduction action between the metal and blah blah blah.
The GEM - generic electronic module - has a pile of relays and wires that control door locks, courtesy lights, keep-alive power after ignition switch shutdown so the windows/radio work after you kill the engine, cruise control?, door locks, automatic headlights(some), remote door locks, alarm,... and some I know nothing about.
Some source of power is being activated when it gets wet. OR a ground is becoming more conductive when it gets wet... or is shorting something to something else.
FOr many things, the computer provides a ground to operate a relay, injector, COP or ???, so if you have a ground being supplied and it is crossed to another wire coming into poor contact, adding some water can make it a GOOD ground for a while, making the relay, etc work when it should not. Just as an example.
tom

 

Thank's for responses. Water getting under hood and into wiring somewhere was my first guess. I will check all block to engine grounds and windshield weatherstripping for leaks and get back to you.

 

Found several things after visual inspection. The rubber piece between the hood weather stripping at the back and fender on passenger side is gone as in not there. There is a data connector on passenger side in front of the heater blower motor that could easily get wet because of this and it does not have a cover on it - should it have a cover? What is that connector for. It looks just like the diagnostic port connector but I couldn't find it in my Haynes manual. The rubber piece looks like it snaps into the body into one hole. I also found a tear in the weatherstripping on the drivers side just above the brake power booster but that shouldn't be a problem. Weatherstripping was very dirty but otherwise OK. Can I get that rubber piece at auto parts store? thanks

 

Couple more things. That diagnostic port ( which a guy told me was for a laptop ) does have a cover on it so I don't think that rubber piece would make any difference but I went and got it plus the weatherstripping for back of hood at a junkyard anyway. Problem recurred again today 9/10/18 with another small twist. When I cut off the radio and removed the key the clock stayed on until I cut the wiper switch on and then the clock went off. Whatever the problem it is clearly of the wipers and radio. I checked all grounds for tightness-seem ok. I was thinking of putting a strip of duck tape over the ECM connection to make sure water isn't getting into it. That's the latest. thanks