1800: 1970 1800E no indicators tell-tale

[sleek lemur]

Am scratching my head about these damn indicators. They gradually failed a couple of months ago, first flashing only 6 or 7 times, then stopping. In the end they failed completely. I bought a new relay and that seemed to solve the problem, except the tell-tale in the speedo doesn't flash, nor the red hazard light tell-tale on the pull-switch. (I had previously bought a new flasher unit from Brookhouse, probably not more than a year ago. At that time it took a couple of attempts before we found the correct one.) The tell tale bulb in the speedo is ok.

I suspected the switch into which the flasher relay plugs, but I have tried another the result is the same. No tell-tales for the indicators or hazards.

Any great ideas ? On the basis that the previous one only lasted a year, could the new flasher relay be at fault? The turn indicator pilot does seem to run off the centre pin of the relay.

https://volvo1800pictures.com/docume...Color_V1.1.pdf

Thanks as always!

Tim

[Ron Kwas]

Tim;

Blinker Element (Relay) is indeed a three terminal type, with one terminal (P) driving the Pilot Light, and it is located on the back of the Hazard Switch, which is really the heart of the blinker system (but having replaced it, you already know all that!). I'd simply try exercising the Hazard Light Switch a few times...they spend most of their life on standby and unused, so the internal contact(s) MAY have gotten some surface contamination (smoker?) or corrosion (live by the sea?) which can result in a slow deterioration of contact, ending in total failure of function as a connection opens up...exercising will sometimes wipe the contact(s) clean and restore function if this is the actual root cause...and if it does, you might want to spray some Deoxit D5 into the internals of the switch for future protection/prevention.

Ref: https://www.sw-em.com/Blinker_Relay_..._Injected_1800

I'd perform some voltage checks to see where power is getting lost/disconnected. Don't forget Hazards are Batt powered (Fuse 9) and Dir Inds are Ign Powered (Fuse 4)...see Link!

Or maybe the blinker, (chinas**t?) has (already) outlived itself...

Let us know what you find. Good Hunting!

[142 Guy]

Just to add to Ron's advice. The turn indicator in the speedo is un switched - the 3rd terminal on the flasher relay is more or less directly connected to the indicator light. No switch contacts involved. In the photo that Ron linked you can see the 31 terminal on the back of the switch that the speedo indicator connects to - pretty much in and out direct connection.

If the indicator light in the speedo is not operating then
- the ground for the indicator light in the speedo has failed (could be a socket problem)
- the bulb has failed although you have confirmed that is not the case
- the connection of the relay 3rd terminal through the switch has been compromised - you could have corrosion on the terminal or a failed crimp connector
- the relay has partially failed - the speedo indicator light is on a separate set of relay contacts from the main signal lights so it is possible to have the main signal lights continue to operate and lose the speedo indicator light. This would be a very uncommon failure.

The indicator bulb inside the hazard switch is controlled by internal switch contacts. However, if the external lights operate when you switch on the hazard switch the internal contacts would appear to be operating correctly. Aside from a socket problem for the bulb the indicator bulb in the switch does require an external ground. Look at the diagram that Ron posted. It shows an external ground connection which is absent from the Volvo diagrams. It has been 7 years since I had my switch out. I don't recall an explicit ground wire for the switch so I expect that this ground is established through the mounting ring for the switch in the dash. Have a look at where the switch mounts in the dash to make sure that it has good metal to metal contact. The only thing that this particular ground affects is the operation of the switch indicator light. Note that the indicator light in the hazard switch is not operated through the third terminal on the relay so that particular type of relay failure would not cause non operation of the hazard indicator bulb.

Bad / flakey ground connections are a significant source of electrical misery on vintage cars. Grounding was a bit of an after thought, frequently relying on mounting screws to establish the grounds. A zinc bearing grease such as Ox-gard at these ground connections can help to improve the ground connection.

[sleek lemur]

Thanks as ever Ron and 142.

The previous flasher relay only lasted a year, so I did suspect quality there.

Swapping the switch made no difference.

Therefore, Grounding as you suggest seems to be to most likely culprit. I will study the difference between Ron's diagram and the wiring diagram I have.

[Ron Kwas]

Guys;

Grounding (i.e. current return path to chassis) is necessary at the SWF switch, only for the function of Indicator Lamp in the knob, otherwise it it will not affect the Directional Indicators, which certainly need their own return current path.

See also: https://www.sw-em.com/emergflash.htm...rade_Procedure [Item 4]

Cheers

[sleek lemur]

Thanks Ron!

Very clear diagram. Hmmm...the likelihood of there being two separate earthing issues seems remote. Hang on! This is my car! Anything electrical is possible!

Will keep you informed.