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Question:

I hope it is okay to post here since the explorer, bronco, and ranger seem to be related. I have a 91 with hi/low/intermittant wipers.  Yesterday, there was a bit of ice on windshield and when I turned them on, they moved a bit and quit.  I moveded them by hand but they will not move under their own power. The 6a circuit breaker seems to be okay, I put a 10 a fuse in it’s place to trouble shoot.  I heard a click under the dash when I go from on to low.   I went to salvage yard and borrowed a used  wiper motor and plugged it in.  It did not work.  My washers do work. My Haynes manual is useless.  It doesn’t show much of a wiring diagram. There must be a control relay or module somewhere.  Anyone want to tell me where it is? Thanks, Wes

Response:

No answers from anyone so I might as well post what I have found. On the wiper motor that has 4 pins. Applying power to the stripped wire and the white wire will make wipers go back and forth.  At this point assuming that the other two pins are used to sense park position of motor.  Just an assumption. Kept turning on and off wiper and heard a click under dash.  Found a grey box about 2 to 3 inch on a side.  The cover comes off and you can see a relay, big diode and other descrete components.  No IC’s! I thought that maybe the relay had burned out it’s contacts so I jumped aroud them.  To bad, I slipped and the relay changed behavior. I removed relay to check with external power to coil. NO and NC contacts are fine. I removed q1, q2, q3 (marked on circuit board along with base, emitter, and collector)  Determined that q3 is toast.   Using a DVM (Fluke 12) I determined that Q1 and q2 are Npn and based on voltage drop, silicon.  q2 and q3 were connected like a darlington pair if I sketched it right.  At this point I am reaching way out there since I last practiced electronics in the late 70’s in Marines. I noticed when I soldered in q2 that the leads were bent such that the collector was swapped with emitter.  I put another npn silicon switching transistor in it’s place since the leads were to short to bend them to fit in correctly. I put the module in place and now I hear a click when going from off to low or high, and now the relay clicks in and out on ittermittant. It is bit faster than before but the relay is working. Now the bad thing.  The wipers still do not move. Is there a relay that does the final switching hidden somewhere.  The little relay inside the module did look a bit light? Thanks, Wes – Hide quoted text — Show quoted text – >I hope it is okay to post here since the explorer, bronco, and ranger >seem to be related. >I have a 91 with hi/low/intermittant wipers.  Yesterday, there was a >bit of ice on windshield and when I turned them on, they moved a bit >and quit.  I moveded them by hand but they will not move under their >own power. >The 6a circuit breaker seems to be okay, I put a 10 a fuse in it’s >place to trouble shoot.  I heard a click under the dash when I go from >on to low.   >I went to salvage yard and borrowed a used  wiper motor and plugged it >in.  It did not work.  My washers do work. >My Haynes manual is useless.  It doesn’t show much of a wiring >diagram. >There must be a control relay or module somewhere.  Anyone want to >tell me where it is? >Thanks, >Wes

Response:

Why not just change the module? BTW, overfusing any vehicle built since the late ’80s is inviting disaster. Wires that used to be 14ga are now 22ga and just wont take the extra current flow. Wiper motors (along with most other accessories) are controlled on the ground side – looking for voltage to be applied will be a losing proposition. Look for grounds to be applied and you’ll be on the right track. — Jim Warman Slave Lake, Alberta, Canada – Hide quoted text — Show quoted text – > No answers from anyone so I might as well post what I have found. > On the wiper motor that has 4 pins. Applying power to the stripped > wire and the white wire will make wipers go back and forth.  At this > point assuming that the other two pins are used to sense park position > of motor.  Just an assumption. > Kept turning on and off wiper and heard a click under dash.  Found a > grey box about 2 to 3 inch on a side.  The cover comes off and you can > see a relay, big diode and other descrete components.  No IC’s! > I thought that maybe the relay had burned out it’s contacts so I > jumped aroud them.  To bad, I slipped and the relay changed behavior. > I removed relay to check with external power to coil. NO and NC > contacts are fine. > I removed q1, q2, q3 (marked on circuit board along with base, > emitter, and collector)  Determined that q3 is toast. > Using a DVM (Fluke 12) I determined that Q1 and q2 are Npn and based > on voltage drop, silicon.  q2 and q3 were connected like a darlington > pair if I sketched it right.  At this point I am reaching way out > there since I last practiced electronics in the late 70’s in Marines. > I noticed when I soldered in q2 that the leads were bent such that the > collector was swapped with emitter.  I put another npn silicon > switching transistor in it’s place since the leads were to short to > bend them to fit in correctly. > I put the module in place and now I hear a click when going from off > to low or high, and now the relay clicks in and out on ittermittant. > It is bit faster than before but the relay is working. > Now the bad thing.  The wipers still do not move. > Is there a relay that does the final switching hidden somewhere.  The > little relay inside the module did look a bit light? > Thanks, > Wes >I hope it is okay to post here since the explorer, bronco, and ranger >seem to be related. >I have a 91 with hi/low/intermittant wipers.  Yesterday, there was a >bit of ice on windshield and when I turned them on, they moved a bit >and quit.  I moveded them by hand but they will not move under their >own power. >The 6a circuit breaker seems to be okay, I put a 10 a fuse in it’s >place to trouble shoot.  I heard a click under the dash when I go from >on to low. >I went to salvage yard and borrowed a used  wiper motor and plugged it >in.  It did not work.  My washers do work. >My Haynes manual is useless.  It doesn’t show much of a wiring >diagram. >There must be a control relay or module somewhere.  Anyone want to >tell me where it is? >Thanks, >Wes

Response:

I have not over fused anything but the thought of looking for grounds is interesting.  Oh, how I would love a complete wiring diagram of the wiper system.   Monday I will try another module if I can find one in the bone yard. I would hate to buy a new one and find that it isn’t it. Wes More time than money. – Hide quoted text — Show quoted text ->Why not just change the module? BTW, overfusing any vehicle built since the >late ’80s is inviting disaster. Wires that used to be 14ga are now 22ga and >just wont take the extra current flow. >Wiper motors (along with most other accessories) are controlled on the >ground side – looking for voltage to be applied will be a losing >proposition. Look for grounds to be applied and you’ll be on the right >track. >– >Jim Warman >Slave Lake, Alberta, >Canada

Response:

I did get an answer about a bad ground but didn’t have a clue as to where to look.  More on that later. Today, I recieved my brand new 100+ dollar turn signal, wiper, hazard, high beam switch assembly.  Ran home with it, dropped the lower plastic shroud and pulled off the left most wiring connecter and plugged it into new switch.  Flipped the switch and hurrah, the wipers wiped.   During this time, I was trying to get the whole wiring harness free and I saw a nylon cable tie thingie that made no sense to me but was keeping me from dropping all the cables down. I was ready to cut it loose at first but being older and wiser, I looked at it a bit.  I saw that on right side it was threaded into a nylon nut.  Okay, lets unthread it.  Now, there is a fine wire inside it.  Stop.  Put it back, back away from the vehicle.   That is the wire that relays the position of the transmission when you move the shift lever on a column mount auto shifter.  No harm done. Back to the switch.  I went into house to get the exploded view the parts man gave me.  Not much help since it was for a floor shift model so this thing wasn’t in it. Still feeling good, I started the truck and turned on wipers one more time to feel the joy.  No joy.  Dead in the water, new switch in place.  The new switch got it to move once so what is going on?   Then I grabbed the wipers by the throat so to say and they seemed to be willing to move if I helped a bit.  Humm, LOOKS LIKE A GROUND! Thanks to Jim & Debb Warman, spammers find their address on your own. That was suggested the first time and 100+ bucks ago. Evidently, my new switch was just enough better on the contact side to make them move once but the next time it wasn’t enough. So I looked on firewall and looked at stud with ground strap to engine and a little black wire to gearbox cover of wiper and gave it a tighten.  Humm, wants to spin, looks like it is on a standoff which does not make sense since it is a ground.  Test wipers, they move, not with the arm ripping authority that I am used to but they work.  Plug in old switch and things still work. So what is on the other side of this stud? Strange that it wants to spin.  Tomorrow I will run a jumper from battery negative to it to see if torque improves with wiper. Yeah, replying to one’s post is bad form but someone in my place searching http:groups.google.com for info will see my whole story and it might help them. Wes KC8SPR W E S S at G T I I dot C O M – Hide quoted text — Show quoted text – >No answers from anyone so I might as well post what I have found. >On the wiper motor that has 4 pins. Applying power to the stripped >wire and the white wire will make wipers go back and forth.  At this >point assuming that the other two pins are used to sense park position >of motor.  Just an assumption. >Kept turning on and off wiper and heard a click under dash.  Found a >grey box about 2 to 3 inch on a side.  The cover comes off and you can >see a relay, big diode and other descrete components.  No IC’s! >I thought that maybe the relay had burned out it’s contacts so I >jumped aroud them.  To bad, I slipped and the relay changed behavior. >I removed relay to check with external power to coil. NO and NC >contacts are fine. >I removed q1, q2, q3 (marked on circuit board along with base, >emitter, and collector)  Determined that q3 is toast.   >Using a DVM (Fluke 12) I determined that Q1 and q2 are Npn and based >on voltage drop, silicon.  q2 and q3 were connected like a darlington >pair if I sketched it right.  At this point I am reaching way out >there since I last practiced electronics in the late 70’s in Marines. >I noticed when I soldered in q2 that the leads were bent such that the >collector was swapped with emitter.  I put another npn silicon >switching transistor in it’s place since the leads were to short to >bend them to fit in correctly. >I put the module in place and now I hear a click when going from off >to low or high, and now the relay clicks in and out on ittermittant. >It is bit faster than before but the relay is working. >Now the bad thing.  The wipers still do not move. >Is there a relay that does the final switching hidden somewhere.  The >little relay inside the module did look a bit light? >Thanks, >Wes >I hope it is okay to post here since the explorer, bronco, and ranger >seem to be related. >I have a 91 with hi/low/intermittant wipers.  Yesterday, there was a >bit of ice on windshield and when I turned them on, they moved a bit >and quit.  I moveded them by hand but they will not move under their >own power. >The 6a circuit breaker seems to be okay, I put a 10 a fuse in it’s >place to trouble shoot.  I heard a click under the dash when I go from >on to low.   >I went to salvage yard and borrowed a used  wiper motor and plugged it >in.  It did not work.  My washers do work. >My Haynes manual is useless.  It doesn’t show much of a wiring >diagram. >There must be a control relay or module somewhere.  Anyone want to >tell me where it is? >Thanks, >Wes

Response: