94 940 no power to Voltage regulator
#1
#2
Not sure what you are asking - here's a wiring diagram
The alternator (6/26) has two wires going to it. (if it's a gas engine) The big red wire (B+) that goes to the starter (6/25, unless it's diesel) then to the battery (1/1)
And - The small red wire (D+) goes directly to the warning light in the instrument cluster. 10/87 is the warning light, 5/1 is the cluster.
The alternator (6/26) has two wires going to it. (if it's a gas engine) The big red wire (B+) that goes to the starter (6/25, unless it's diesel) then to the battery (1/1)
And - The small red wire (D+) goes directly to the warning light in the instrument cluster. 10/87 is the warning light, 5/1 is the cluster.
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Stellar (01-17-2022)
#5
When you turn the key on power goes to the warning light and is grounded in the alternator. Bulb is illuminated. Once the alternator is charging there is power at the D+ terminal and still power from the key - battery voltage on both sides of the bulb makes the bulb go out - indicating that it is charging.
To test - Unplug with small red wire at the alternator, touch it to ground with the key on and see the alternator warning light comes on - if it does that circuit from the key through the bulb to the alternator is good. If the bulb does not light - bad bulb, bad connection somewhere in that circuit. If the bulb lights up in the previous test but does not when plugged in - And the alternator case is grounded and large B+ wire has battery voltage - you have a bad alternator. (or possible worn out brushes in the voltage regulator) Make sure the ground wire )if equipped) on the alternator is ok.
To test - Unplug with small red wire at the alternator, touch it to ground with the key on and see the alternator warning light comes on - if it does that circuit from the key through the bulb to the alternator is good. If the bulb does not light - bad bulb, bad connection somewhere in that circuit. If the bulb lights up in the previous test but does not when plugged in - And the alternator case is grounded and large B+ wire has battery voltage - you have a bad alternator. (or possible worn out brushes in the voltage regulator) Make sure the ground wire )if equipped) on the alternator is ok.
Last edited by hoonk; 01-17-2022 at 03:32 PM.
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Me512Mike (01-20-2022)
#7
Well no battery light. Just borrowed a ohm meter to do a complete check. But if no juice coming out of red wire voltage regulator won't activate right?? So sounds like bad connection at instrument cluster ?
So you have to pull cluster out to check ?
& how does it come out? I did find video on how to check alternator , battery & cables
So you have to pull cluster out to check ?
& how does it come out? I did find video on how to check alternator , battery & cables
#10
#14
Vida only has instructions for the 940se/960
Here's something courtesy of friends across the pond for a 940 instrument cluster removal.
https://www.volvoclub.org.uk/faq/Ele...ClusterRemoval
Here's something courtesy of friends across the pond for a 940 instrument cluster removal.
https://www.volvoclub.org.uk/faq/Ele...ClusterRemoval
#16
#18
Using your ohmmeter make sure the D+ wire is continuous from the alternator (unplugged from the alternator) to terminal 16 (small red wire) in the c plug or directly to the bulb connector with the c plug attached. Make sure you have battery voltage to terminal 4 (blue/red wire) on the d plug (the other side of the bulb that gets power from the ignition switch) or on the other side of the bulb connector.
Does your alternator warning light not illuminate when the key is on and the D+ wire is grounded? Bad connection or bad bulb is about your only choice. Have you swapped in another bulb? (there's 10 or so to choose from)
Does your alternator not charge? Are you calling the D+ wire the "exciter" wire? Sorry I've never checked for "power" at the "exciter" wire (in 45 years). First I measure alternator output, if warning light is not working that can prevent charging on some cars. If either is wrong - figure out (from supplied Diagrams) why. If warning light works when D+ is grounded and alternator does not charge - The alternator (or regulator) is bad. Am I missing something?
Does your alternator warning light not illuminate when the key is on and the D+ wire is grounded? Bad connection or bad bulb is about your only choice. Have you swapped in another bulb? (there's 10 or so to choose from)
Does your alternator not charge? Are you calling the D+ wire the "exciter" wire? Sorry I've never checked for "power" at the "exciter" wire (in 45 years). First I measure alternator output, if warning light is not working that can prevent charging on some cars. If either is wrong - figure out (from supplied Diagrams) why. If warning light works when D+ is grounded and alternator does not charge - The alternator (or regulator) is bad. Am I missing something?
#19
I May not be explaining clearly: Ok here we go : D+ (lil red wire) aka: Exciter Wire is Dead. History : I've had car 2yrs don't remember battery light ever workin.
SO did test. D+ Exciter unplugged w key on no juice. Made a jumper battery to D+ : started car put meter on battery its discharging, connected jumper system Started charging , unplug jumper no charge. Pulled Cluster out checked bulb (10 ? )out of Cluster it works ( why need a list of which bulb which) tighted all the screws none really loose. Going to clean plug connections then ????
SO did test. D+ Exciter unplugged w key on no juice. Made a jumper battery to D+ : started car put meter on battery its discharging, connected jumper system Started charging , unplug jumper no charge. Pulled Cluster out checked bulb (10 ? )out of Cluster it works ( why need a list of which bulb which) tighted all the screws none really loose. Going to clean plug connections then ????