|240 Headlight Relay Page
|UPDATED: May 27, 2021 CONTACT|
|D O M
A I N S
|Mysteries of the 240 Headlight Step Relay||Eliminate the 240 Step Relay
|How to Remove Terminals||760-960 Headlight Relay
|Headlight Relay Harnesses
||Bosch Terminal Designations
This headlight relay was used in these early 240s.
PN 1307991 Headlight Step Relay.
Later 240s also got the 1307991 step relay, but these cars were also fitted with a "MAIN" (in-dash) headlight relay.
Here's a look at the main headlight relay in the 240 center dash.
This relay one is found next to and to the LEFT of the power door locking relays, which can be seen in the photo.
This photo was taken with the entire dash removed. You should be able to get to it by removing the center air vents and pushing the inner plastic air duct out of the way or by removing the center dash console as shown in the below VIDEO. No, Volvo didn't make it very easy.
ZINC PASTE (ACZP)
If we can just just keep our electrical connections clean and tight, almost all of the electrical issues would be gone forever. That would be nice, right?
I have owned a number of Volvos over the last 30 years and my current 240 is way over 30 years old. It almost never has electrical problems. Nothing like the endless numbers of other 240s out there that I hear about so often. What's the difference you ask? The difference is that my 240 has been always garaged all of its life. Why is that important? Because leaving any car out in the open elements for years and years slowly introduces corrosion to grounds and power connections until things begin to go wrong.
So if you own one of those cars that has been outside forever, it's not too late. You can still clean as many grounds and electrical connections as possible.
And while you're at it, I recommend that you smear a little anti-corrosive zinc paste on those connections.
Many people in the Volvo community gravitate toward Ox-Gard, which does a similar job.
The below information was contributed by Ron Kwas and should come in very handy to old Volvo owners:
Anti-Corrosive Zinc Paste (a generic name for zinc dust contained in a grease) was originally developed for and later required by electrical codes for use on alumunum to copper electrical connections (or other dissimilar metal connections). No, it's not the same as Dielectric Grease, which is often incorrectly recommended. Dielectric Grease can offer some protection in the form of encapsulation from moisture, but it also carries with it the potential disadvantage of locking in moisture or corrosion which may have already begun. Anti-Corrosive Zinc Paste (or ACZP) is the next evolution of the encapsulation principle, because zinc (the lowest on the Galvanic nobility chart) neutralizes corrosion on a micro-scale to truly protect connections on a long-term basis during the encapsulation, INCLUDING an added protection from corrosion which may otherwise begin to form in that connection.
Ron uses and recommends Penetrox A (by Burndy). Many Volvo fans are familiar with Ox-Gard, which is a similar zinc compound. Ron and I are huge advocates of treating ALL electrical connections on our cars (except of course High Voltage Ignition connections) with a suitable version of this material.
You can learn more about this stuff at Ron's page here:
Unlocking the Mysteries of the Volvo 240 Headlight Step Relay.
And Test Procedure.
This step relay is found in the Volvo 240 from 1975 to 1993. It will be seen under your hood on the left inner fender, except for the 1993 model, where it was switched to the RIGHT inner fender.
This relay was made in two different versions (same part number), however both versions function exactly the same and both are interchangeable.
The EARLY version can be identified below with two less contacts. The extra contacts in the LATER version do not change the function at all. It just adds redundant contacts.
Regarding these early or later relays being interchangeable, THEY ARE, however keep in mind that if you use an early relay on a later car AND your car just happens to use those extra two contact pins, you'll need to re-wire those contact pins to the two outside pins.
MOUNTING BRACKET CHANGE
If you're observant, you'll notice that the mounting bracket is on the opposite side on the late relay. This doesn't affect the function, but it might affect the harness plugs, because if you use a newer relay in an older car, the harness plugs will need to be twisted 180 degrees to work. That will add unwelcome stress on your wires.
A simple solution is shown below.
It's a very simple task to pry open the crimps and remove the relay from the housing. Then the internal relay portion can be turned 180 degrees and re-installed.
This literally takes 30 seconds.
This step relay has a LATCHING function. A latching function works like this:
You can click and release a momentary button or switch (in this case it's pulling back on the 240 high/low beam lever) and the relay will then LATCH (or lock) in one position or another. It reverses with each pull of the lever.
So with this step relay, one click latches "ON" the low beams. And another click latches "OFF" the low beams and latches "ON" the high beams.
In a 240 the latch function is activated by a GROUND signal, which is created by pulling the high/low beam lever.
Here's a short video on the step function between high and low beam.
240 Relay Function and Testing
I have created the below PDF if needed (same info as shown above).
|How to Use
Commonly Available Relays
to ELIMINATE your Volvo 240 Headlight Step Relay
This modification will accurately reproduce the functions of the original Volvo step relay. It simply copies and can replace the Volvo step relay and connectors.
It does not eliminate any need or recommendation you may have for additional headlight relays to feed high current headlights if you have them. Feel free to add those if needed.
This is a good project for anyone with any older Volvo, especially if you have or want to to upgrade to brighter bulbs or headlights.
For the best info I know, begin reading Daniel Stern's page on this subject. He also has several useful diagrams for designing and building your own relay harness.
Here are some Volvo specific diagrams that have been available on-line for many years. These use the same principles:
Wagonmeister is offering ready made 240 headlight relay harnesses, like this one below.
This relay is PN 1392900 and has been no longer available new for many years.
Used relays like these are showing up online for OVER $100!
If YOU can help, I would be happy to work out a similar solution to ELIMINATE THIS RELAY in a similar way as the 240 relay. I need help from someone out there with one of these cars and maybe someone willing to lend me a relay like this for some testing.
So far very people few have spoken up.
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