1990 Volvo 240DL Wagon 176k

I just replaced an old wiper motor with a re-manufactured Cardone. The old motor struggled to run when the temp was 20 degrees or below. The swap out went smoothly and the replacement worked fine, although the temp has not dropped to 20 degrees since the swap out so the cold functioning has not been confirmed. Regardless, the trouble I have now that it's a week later and there is no power to the motor. No voltage read from any of the female connector leads. I have 14V across #2 fuse. The horn, which is on the same fuse, works OK. The interior wiper switch activates the front washer, rear washer, and rear wipers. Could the interior switch be the culprit for the front wipers not getting power? Any suggestions on how I should proceed to trouble shoot?

FYI
From an earlier thread I gleaned that the front wiper motor wiring is brown = low speed, green = high speed, yellow = always on (return to home), and white-black = intermittent run.

 

if you have volts 'across' a fuse, then that fuse is blown.

 

My bad choice of word about the fuse... I was trying to say that on both sides of the fuse I have 14 volts - put one meter probe on one side of the fuse terminal and the other probe on a door frame bolt - then repeated on the other side of the fuse terminal.

 

then yeah its probably the wiper switch. if you can dig into the steering column, you could probably jumper around the switch, and if the wipers move, then you'd know that would be the problem

 

at the wiper switch, per the 1990 240 electrical 'greenbook',...

pin 53 - brown, normal speed
pin 53b - green - high speed
pin 53a - yellow - power from fuse 2
pin 31b - white - to intermittent relay
pin "I" - red - to intermittent relay
pin "P" - blue-yellow - to intermittent relay and washer pump motor

all of these go to a 6-pin plug that goes into the back of the wiper stalk

in normal wiper mode, the wiper switch connects pin 53a (power) to 53. in high speed mode, it connects 53a to 53b.

The wipers should work in high and low regular without the relay, that the relay is only for intermittent mode, and the automatic several wipes after squirting.

fuse 2 power also takes a yellow wire directly to the wiper motor, this provides power so the wiper always goes home when its switched off.

 

The connector at the interior wiper switch has a terminal with with 2 yellow wires. There is 12 volts there. Could one of these yellow wires be the one that goes directly to the wiper motor? If yes, and I do not have any voltage at the yellow terminal at the wiper motor connector, then that would indicate the problem is between interior switch connector and the wiper motor connector, right? I re-checked the yellow terminal at the wiper motor with the connection undone at the interior switch - again 12V at interior and 0V at motor. I jumpered at the interior switch connector the yellow to brown - no motion of the wipers. So where might I go from here?

FYI
Voltages at the interior switch connector with ignition on:
yellow - 12V
white - 0.5V
brown - 0.5V
Red - 0
green - 0.5V
blue/yellow - 0

 

yeah, the schematic shows it wired either of two ways... fuse 2 to wiper switch to motor, or fuse 2 to motor to wiper switch.

either way, that yellow power at the motor is ONLY so the motor goes 'home' if the regular power (green or brown) is cut off.

if there's 12V at the yellow wire at the wiper stalk, but 0V at the motor, then the wire is broken somewhere in between.

no connector is shown. the drawing /looks/ like the harness goes from the ignition switch and wiper switch across the firewall to the wiper motor, can't tell if this is inside or outside the firewall (and its raining outside, so I'm not going out to look at the 87 240 in my driveway, ahhahah). The harness continues past the motor to a ground point on the right fender near the washer juice bottle and also to the washer juice pump.

when you measure voltage at the motor, are you measuring it relative to the motor body, or are you using engine block ground (near the fuel rails), or what? does your harness have a ground screw for the wiper motor? (some do, some older cars don't). I would check the voltage at the yellow wire using both the wiper motor body and the engine block as a ground...

the intermittent wiper timer/relay is grounded either on the left side of the tranny hump forward of the shifter, or to the ground point on the inside of the front left fender forward of the fuse panel (along side the clutch-pedal-you-probably-dont-have)

 

Oh man, I'm eating me a big 'ol piece of humble pie right now.

Your last reply got me thinking and I rechecked the yellow wire at the wiper motor connection and used the block as a ground and got 12V. I was using the head of a bolt on the firewall that had a ground-wire running to the block. I guess there was enough corrosion on the head the bolt so I didn't get a good ground. The wiper motor's ground is a tab that is sandwiched between one of the motor mounting legs and the firewall - tighten that bolt down and problem solved.

Sorry to waste your time with my stupidity. Thanks for your help.

 

no problem. the number one method of troubleshooting electrical circuits is to follow the current flow

my 'secret' for reliable electrical connections... a 'deoxit d100 pen', looks like a felt pen, but dispenses a thin layer of deoxit electrical oil... I clean contact surfaces with a soft clean pink pencil eraser, then put a dab of D100 on the contact, and bolt it down or plug it in or whatever.


this pen is enough for 1000s of uses. when you first get the pen, the point is dry, its spring loaded, so take a small wad of paper towel, and hold the pen point down and repeatedly press down on the tip til it starts to ooze oil onto the paper.

 

Hi Pierce My 1990 Volvo 240Dl wagons windshield wipers wont work, I checked the fuses and they are good. What should I check next ? please let me know I live in Northern California and its usually wet....Help thank you Kathleen

 

urbanfinch: have you done the tests outlined above in this thread?