Small Coil what’s it for?

RichG

RichG

Daily Driver
Hi Guys I am close to finishing my restoration and this site has been keeping me sane along the way so many thanks.
I’m just on snagging and have the small coil unit smoking when in the side light position could somebody let me know what it does as I can find it on the wiring diagram and also have I connected the wires up correctly?
Many thanks again
 

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Definitely the blower fan speed resistor. Looks like yours is RHD, unless the image is flipped?

Usually mounted on the end wall of the scuttle. Should not be connected to the light circuit in any way shape or form

EDIT: visit the xWeb Wiki & get the Electrical Diagnostic Manual - it may not be your model year, but the overall diagrams are much easier to read than the whole-car 'nervous system"

Update your sig with market, year & model version (Carb, EFI, etc.,) as there are many small variations
 
lookforjoe said:
Definitely the blower fan speed resistor. Looks like yours is RHD, unless the image is flipped?

Usually mounted on the end wall of the scuttle. Should not be connected to the light circuit in any way shape or form

EDIT: visit the xWeb Wiki & get the Electrical Diagnostic Manual - it may not be your model year, but the overall diagrams are much easier to read than the whole-car 'nervous system"

Update your sig with market, year & model version (Carb, EFI, etc.,) as there are many small variations
Click to expand...
Many thanks will take a look at the diagram and update my sig
 
No winners so far 😲 - this is actually a resistor fitted to later 1500 model cars which feeds the headlight dipped beam circuit when the lights are in the side light position. The effect is to have the raised headlights dimmed when on the side (parking) lights. There are two 7.5A fuses in an add-on block in the fuse box that takes the return from the resistor and jumps onto the the dip beam circuit. Maybe just a euro thing? It's a good plan as why have the pods up on side lights with nothing illuminated? Unfortunately it just puts more stress on the slide switch as now there's extra un-relayed current on side position too :eek: This is a factory "mod" that goes hand in hand with 2 relays that are are also in add-in blocks: a black one in a black base and a brown one in a yellow base. I've had an '87 and '88 and both have these - the black one switches in the resistor and the brown does nothing useful as the feed to the relay coil (that comes from the slide switch) also feeds the relay contact that goes off the stalk dip-switch - it looks like it was a factory attempt to (finally) relay the dipped beam headlight circuit, but they then scored an own goal when implementing it :oops: The brown relay is the poorest quality available and the slightest squeeze causes it to switch (not good in cramped fuse box) - it's really just another weak link in the headlight chain and best removed so that the contacts in the base are jumped to restore some reliability. If it mis-switches you loose the dipped circuit instantly :(

It really shouldn't smoke, but it will get hot in the side light position as it's dropping 6v or so - perhaps it just covered in some cleaner/degreaser that's burning off. It you do find it in a wiring circuit, let me know, but 29 years on I'm still looking... :)
 
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Ics19 said:
No winners so far 😲 - this is actually a resistor fitted to later 1500 model cars which feeds the headlight dipped beam circuit when the lights are in the side light position. The effect is to have the raised headlights dimmed when on the side (parking) lights. There are two 7.5A fuses in an add-on block in the fuse box that takes the return from the resistor and jumps onto the the dip beam circuit. Maybe just a euro thing? It's a good plan as why have the pods up on side lights with nothing illuminated? Unfortunately it just puts more stress on the slide switch as now there's extra un-relayed current on side position too :eek: This is a factory "mod" that goes hand in hand with 2 relays that are are also in add-in blocks: a black one in a black base and a brown one in a yellow base. I've had an '87 and '88 and both have these - the black one switches in the resistor and the brown does nothing useful as the feed to the relay coil (that comes from the slide switch) also feeds the relay contact that goes off the stalk dip-switch - it looks like it was a factory attempt to (finally) relay the dipped beam headlight circuit, but they then scored an own goal when implementing it :oops: The brown relay is the poorest quality available and the slightest squeeze causes it to switch (not good in cramped fuse box) - it's really just another weak link in the headlight chain and best removed so that the contacts in the base are jumped to restore some reliability. If it mis-switches you loose the dipped circuit instantly :(

It really shouldn't smoke, but it will get hot in the side light position as it's dropping 6v or so - perhaps it just covered in some cleaner/degreaser that's burning off. It you do find it in a wiring circuit, let me know, but 29 years on I'm still looking... :)
Click to expand...
your a star i thought i was going mad when Hussein said it wasn't related to the lights as it definitely smokes in the side light position only yes please if you can check if i have wired it up correctly as im still investigating but its starting to make more sense now after your explanation. i found that the 7.5A fuse holders were badly corroded so i have replaced those with new holders but still smoke
 
I've had a look at an '88 and the wiring is same as yours - the arrangement is a simple centre fed coil with a take offs for the lights at each end. Red comes from the add-in black relay 87a once the pods are raised AND you're on side lights only - the grey and grey/black go to the 7.5A fuses and then off to the headlights.

late_dim_dip_coil.jpg

Have you checked the voltage at the coils and/or lights? Do the headlights both appear a similar dimness when on sides? Have you or a PO added a bypass relay for the slide switch yet? As I mentioned, the original dim coil mod isn't good for the slide switch, so really needs a relay too if you wish keep the functionality.

For reference for anyone interested, here's the mystic black and brown relays and fuses in untouched form. I've seen a UK 'D' registration car (1 August 1986 – 31 July 1987) and that didn't have the relays/coil, but that car could have been built in '85, so maybe the mod was possibly an '86 onwards thing?

late_fusebox_relays.jpg
 
I few general thoughts relating to all this:

The similar design resistor coil used for the heater blowers seems to increase considerably in its resistance values over the years. I imagine this one does too. That will do two things; lessen the level of light from the headlights when the feed goes through this, and increase the load on the switches.

I've always considered this type of resistor coil as a "fire starter". Especially when is lives in a exposed area where dry leaves and similar debris collects on them. I prefer to change the heater blower resistor pack to a newer technology style....there's a few to choose from. That could be done here of you wished to retain the feature.

I've said it before, but I'll repeat it. I think (as in my opinion is) this should be eliminated. The headlight circuit design is already overly complex and problematic. This is exactly one of those reasons why.

Those extra relays; the 'black' one looks to have the Bosch # for a standard relay, but the "brown" one shows it to be a "change-over" relay. The headlight pod "up and down" relay is also this type. But no idea how all of this resistor system is wired into the rest. I'm just commenting on the types of these relays. Interesting idea for "daytime running lights" in general though.
 
I broke out my fancy new multimeter (I've really just been looking for an excuse to use it) and it seems that on my 85' USA spec car with A/C, it is in fact the blower motor resistor. I initially thought it was the resistor for the two speed wipers but it appears not.

When the blower is on setting one, I get ~3v across red to black and white to black.

In setting two, I get 0.5v across white to black (seems a bit low but keep in mind the terminals are quite rusty so it could be a bad connection with my meter).


I guess it is possible in this case, that depending on year and spec, it is used for different purposes?
 
Jonohhh said:
I broke out my fancy new multimeter (I've really just been looking for an excuse to use it) and it seems that on my 85' USA spec car with A/C, it is in fact the blower motor resistor. I initially thought it was the resistor for the two speed wipers but it appears not.

When the blower is on setting one, I get ~3v across red to black and white to black.

In setting two, I get 0.5v across white to black (seems a bit low but keep in mind the terminals are quite rusty so it could be a bad connection with my meter).


I guess it is possible in this case, that depending on year and spec, it is used for different purposes?
Click to expand...
I'm not sure but I think the resistor on the headlights (as shown above) was only on certain European models. So your US spec car won't have that one. The HVAC blower will have it. The wipers do not. But the one for the HVAC is located next to the wiper motor, so it may appear to go to it.

The readings you are getting are very low. I'm sure a sign of excess resistance. But apparently that isn't too uncommon. In the past there have been a lot of complaints of the blower not fast enough to make much difference. Several owners have added relays to give additional current to the blower circuits. But if this resistor unit has excessive resistance, then that is only something of a bandaid and could potentially cause bigger problems. In my opinion the first step will be to replace the resistor pack with a new one. Then add relays to take all load off the controls.
 
Ics19 said:
No winners so far 😲 - this is actually a resistor fitted to later 1500 model cars which feeds the headlight dipped beam circuit when the lights are in the side light position. The effect is to have the raised headlights dimmed when on the side (parking) lights. There are two 7.5A fuses in an add-on block in the fuse box that takes the return from the resistor and jumps onto the the dip beam circuit. Maybe just a euro thing? It's a good plan as why have the pods up on side lights with nothing illuminated? Unfortunately it just puts more stress on the slide switch as now there's extra un-relayed current on side position too :eek: This is a factory "mod" that goes hand in hand with 2 relays that are are also in add-in blocks: a black one in a black base and a brown one in a yellow base. I've had an '87 and '88 and both have these - the black one switches in the resistor and the brown does nothing useful as the feed to the relay coil (that comes from the slide switch) also feeds the relay contact that goes off the stalk dip-switch - it looks like it was a factory attempt to (finally) relay the dipped beam headlight circuit, but they then scored an own goal when implementing it :oops: The brown relay is the poorest quality available and the slightest squeeze causes it to switch (not good in cramped fuse box) - it's really just another weak link in the headlight chain and best removed so that the contacts in the base are jumped to restore some reliability. If it mis-switches you loose the dipped circuit instantly :(

It really shouldn't smoke, but it will get hot in the side light position as it's dropping 6v or so - perhaps it just covered in some cleaner/degreaser that's burning off. It you do find it in a wiring circuit, let me know, but 29 years on I'm still looking... :)
Click to expand...
That's a whole new one for me. I have an '87 US model, and no relay for dimmed low beams.
 
ArtBasement said:
and no relay for dimmed low beams
Click to expand...
Do you mean no "resistor" (like in this thread) or no "relay"? I don't think any US spec X has relays for the headlight light bulbs. And the same for the resistor - I believe it was a UK thing for local requirements (kind of like daytime running lights).
 
Dr.Jeff said:
Do you mean no "resistor" (like in this thread) or no "relay"? I don't think any US spec X has relays for the headlight light bulbs. And the same for the resistor - I believe it was a UK thing for local requirements (kind of like daytime running lights).
Click to expand...
Right, I meant resistor. I got confused. Weird that they'd want dimmed low beams in addition to the running lights.
 
Dr.Jeff said:
I'm not sure but I think the resistor on the headlights (as shown above) was only on certain European models. So your US spec car won't have that one. The HVAC blower will have it. The wipers do not. But the one for the HVAC is located next to the wiper motor, so it may appear to go to it.

The readings you are getting are very low. I'm sure a sign of excess resistance. But apparently that isn't too uncommon. In the past there have been a lot of complaints of the blower not fast enough to make much difference. Several owners have added relays to give additional current to the blower circuits. But if this resistor unit has excessive resistance, then that is only something of a bandaid and could potentially cause bigger problems. In my opinion the first step will be to replace the resistor pack with a new one. Then add relays to take all load off the controls.
Click to expand...
Within a month of X1/9 ownership, I resorted to a "I don't ask questions" approach to Italian electronics that *seemingly* work fine on the surface.

Those voltage drops do indeed seem a bit low, but somehow... somehow...the steps between the 3 blower speeds are even and appropriate. Not sure how- thanks for confirming those numbers to be a bit odd.

I tried to ignore the number the multimeter gave me.


I don't have the AC System working yet as there is a massive leak somewhere, so I'm sure once it's all fixed I'll find it to be inadequate.
 
Last edited:
Ics19 said:
I've had a look at an '88 and the wiring is same as yours - the arrangement is a simple centre fed coil with a take offs for the lights at each end. Red comes from the add-in black relay 87a once the pods are raised AND you're on side lights only - the grey and grey/black go to the 7.5A fuses and then off to the headlights.

View attachment 47808
Have you checked the voltage at the coils and/or lights? Do the headlights both appear a similar dimness when on sides? Have you or a PO added a bypass relay for the slide switch yet? As I mentioned, the original dim coil mod isn't good for the slide switch, so really needs a relay too if you wish keep the functionality.

For reference for anyone interested, here's the mystic black and brown relays and fuses in untouched form. I've seen a UK 'D' registration car (1 August 1986 – 31 July 1987) and that didn't have the relays/coil, but that car could have been built in '85, so maybe the mod was possibly an '86 onwards thing?

View attachment 47807
Click to expand...
thanks so much for the photographs and advice it gave me confidence to leave it on side lights for a while and i think you were right in that it was burning off cleaning materials and your explanation was perfect and as you say the main lights dim when your on side lights only. the resistor does run very hot so i will modify at some point but i wanted to keep the car original during the restoration so that i don't introduce self inflicted problems . MOT next thursday so big thanks i would have struggled untaggling that one especially as it doesn't exist on a wring diagram seemingly
 
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