79 Diesel L electrical help

[mnaussie]

I picked up a 79 Diesel L, had been sitting since approx 1996, I have got it running and all my lights working properly (and fixed the ghetto headlight wire job).

It has Factory air and the optional 5sp
Yes I have a Bentley's more than one for MK1 and several other manuals also

Now I am trying to sort out the following;
cabin blower fan not working (this is the type with 3 levers for the stacked on top of each other)
Temp Gauge not working
Fuel gauge not working (tank is full to the gills as I picked it up)
Washer pump (works when hot wired)
Radiator Fan (works intermittently when cold is selected but otherwise not)

I am not great with electrical, just very basic stuff

[Bowcaster]

I picked up a 79 Diesel L, had been sitting since approx 1996, I have got it running and all my lights working properly (and fixed the ghetto headlight wire job).

It has Factory air and the optional 5sp
Yes I have a Bentley's more than one for MK1 and several other manuals also

Now I am trying to sort out the following;
cabin blower fan not working (this is the type with 3 levers for the stacked on top of each other)
Temp Gauge not working
Fuel gauge not working (tank is full to the gills as I picked it up)
Washer pump (works when hot wired)
Radiator Fan (works intermittently when cold is selected but otherwise not)

I am not great with electrical, just very basic stuff

Start with new relays and a can of electric cleaner. Gooooood luck.

[SpeedieD]

Exactly start cleaning the wires. After this use a voltmeter to check if there is juice coming.

This could be a relais, wire or fusebox issue.

[rabbitnothopper]

fuel level sender inside pump probally rotted, remove seat,remove cap, pull level sender
you can check it for ohms before pulling it out
if you have a simple 2 pin then:
27-33ohms is full
233-270ohms is empty (varies)
anything over 300ohms is bad, need to clean it
REPLACE THE BIG O RING!!!

other reasons:
the voltage stabilizer on the cluster needs to be replaced or tested
it controls several items in the dash
it has 3 "feet/legs" and its an IntegratedCircuit (IC) you will know it....

relay
check your X relay (aka load relay)
if your defroster unit doesnt work (12v) then that is most likely the issue
it controls wiper, blower, defroster, etc (all the heavy amp items)

if your radiator fan only works when "cool" is selected on the AC then you need to check the switch on the radiator
there is a bypass relay here which is designed to do this, its a feature of AC cars
the switch is located at the lower driver side under the battery at the bottom
dont pull the switch out, just check it
jumper the two wires together and the fan should come on no matter what (car off)
if they dont then you have a problem
then you can test the OHMS resistance of the switch itself as it heats up
start when cold, check ohms
start car, watch if ohms drop as the radiator temp warms up


ok, washer pump
id start by checking the wires on the column
the bentley has troubleshooting information for this
find it, it will help you
otherwise as you have most of it apart checking it
verify the contact on the pull lever is actually making a contact it may be dirty or bent
you cant really see it unless you remove the steering wheel etc and have the switch in your hand


let us know what worked, what didnt, if you have more questions
and post pictures, we luvv pictures.........

thanks

[mnaussie]

Checked the sending unit last night I need to check again today (I think I got 33ohm)

I will take some pictures and try to get them posted, I have a feeling I am missing the load relay? The relays on the fuse box are the following
Glow plug
left side flasher
right side flasher
321919505

AC Fan Relay 171959143A on the steering column
Relay for the radiator fan 321919505 also on the steering column

The wipers work (both speeds) and when I pull the lever for the washer the seat belt/brake warning lights light up?

The radiator fan kicks in when you bridge the thermo switch on the radiator

That's about where I am at right now, I have the steering wheel pulled so I will check the washer switch on the column today.

Thanks for the tips and advice so far

[mnaussie]

Ok so I now have the washer pump working, but the seatbelt/brake light light up on the dash

I have power at the rear defrost switch
Radiator fan works when you jump the sensor in the radiator under the battery
Radiator fan kick in at different speeds when the wires are jump on the relay for the AC

Still no cabin fan, and I have not run the car today to warm it up and check resistance on the thermo switch.

[rabbitnothopper]

good news is that you tested the wires on the thermo switch and the wires work
therefore your switch is probally bad and needs replacement

you should go stock and match it to your thermostat in the waterpump
or just replace it exactly to the same temp stamped on the switch

AC radiator fans have high and low speed (3 pin connectors)

i am not sure why your blower does not work, more digging should illuminate this

the seatbelt light is troublesome, mine will generally illuminate doing wierd things no matter what
ignore it at all costs unless you must fix it
i blame it mostly on the strange wiring of VW

my 81 the seatbelt light flicks on every time the rad fan kicks on or off (relay related) it is only on for a split second
ignore it
my 78 similar situation, the light works normally (it goes off) but it will remain on and slowly slowly slowly fade away after shutting the car off
ignore it....

find the manual page for the relays & fuses in your bentley to check the fusebox

i believe socket K is the load reduction relay
you can test this relay by removing it and shorting pin 85 to 86 if it clicks then it works
if no click then it does not work
since your wipers and your rear defrost unit work (via the switch) then your load relay works

[rabbitnothopper]

found this for you

this item usually controls a few items on the dash

[mnaussie]

Will check that one tomorrow thanks

I go the heater / AC fan sorted, Dam Mice eat through the power at the bottom of the resistor bus next to the motor! Soldered a new wire in and all seems good

I did check and I am getting power to the instrument panel so it might be the voltage stabilizer I will check it tomorrow.

I am getting there slowly
Thanks Guys

[mnaussie]

It ended up been the voltage reg, I just swapped one from another cluster I had and Bam!

Thanks for the help guys

I only have the thermo switch to swap out and replace my windshield and should have this little rabbit on the road

Now time for a few of these

[rabbitnothopper]

It ended up been the voltage reg, I just swapped one from another cluster I had and Bam!

Thanks for the help guys

I only have the thermo switch to swap out and replace my windshield and should have this little rabbit on the road

Now time for a few of these

right on, glad you got it running

troubleshooting and diagnosis helps save the day again

[fatmobile]

Will check that one tomorrow thanks

I go the heater / AC fan sorted, Dam Mice eat through the power at the bottom of the resistor bus next to the motor! Soldered a new wire in and all seems good

I did check and I am getting power to the instrument panel so it might be the voltage stabilizer I will check it tomorrow.

I am getting there slowly
Thanks Guys

If the heater fan hasn't melted pin 19 of the blue plug yet,..
you should relay it on high.
I just put the relay next to the fan in the rain tray and ran fuse/wire from the battery.

[rabbitnothopper]

If the heater fan hasn't melted pin 19 of the blue plug yet,..
you should relay it on high.
I just put the relay next to the fan in the rain tray and ran fuse/wire from the battery.

good tip, that is about 20-30 amps flowing through that one wire from the switch