Volvo 240 Ambient Temperature Gauge
Unfortunately, ambient temperature gauges are as scarce as hen's teeth. Only occasionally does a used unit become available for sale, and Volvo Classic Parts has long since run out of inventory.
The good news is that analogue versions are still offered by VDO by their
Instrument Division. (VDO is now owned by the German parts supplier Continental Automobile.) These gauges mount in either of the 2-1/16" diameter supplemental mounting bays on the centreline side of the instrument cluster in the dashboard's instrument frame. (Rather than saying on the left side, for RHD vehicles, or on the right side for LHD vehicles.)
The most common instrument customization for 240s is the replacement of the clock in the cluster (part no. 1398884) with a tachometer (part no. 1398883). This was an option when the vehicle was ordered. But a VDO 'barrel' clock (part no. 1188269, repl. by 1394753) was also available at additional charge for mounting in one of the supplemental bays. The barrel clock was held in place with three rubber retaining clips (part no. 1259737). The clock was finished with a plastic bezel that clipped in place around it, and the lower bay was hidden with a plastic cover that also clipped on.
A second customization was to install VDO's OEM ambient temperature gauge in the remaining supplemental bay using the same mounting arrangement. Today, VDO's aftermarket gauges are cast with threads on the body of the barrel which secure a 'Spin-Lok' retainer. The retainer presses against the back side of the instrument frame, securing the gauge. However, since the 240's instrument frame is pre-cast with the mounting bay using the clips, the retainer can be discarded. Once the gauge is mounted, the plastic cover that hid the bay is replaced with the same bezel (part no. 1259730) used for the barrel clock, but installed upside down. (Both the bezel and retaining clips are still available from Volvo dealers as of Jan 2020.)
VDO's ambient temperature gauges calibrated in Fahrenheit (VDO item no. 397-154) or Celsius (VDO item no. 397-155) are available only as a kit that includes the gauge, temperature sensor with mounting bracket, cable harness and lamp socket. The original Volvo part no. is 1188815 for Fahrenheit and 1129311 for Celsius. The kit must be purchased from a VDO dealer of which there are plenty in North America. VDO's web site provides a list and dealer location. I used
Summit Racing Equipment because of their free shipping to Canada. Cost was ~$US120 plus import fees and taxes.
Also, note that the VDO installation mounting instructions are not available from the web site, and are not included in the kit package. Call the Technical Service department and they will email a copy. Critically, these instructions contain the circuit diagram showing the grounding. The easiest way to connect the gauge electrically is to use the output (brown wires) from the panel light dimming rheostat for the instrument face illumination bulb, and the input (green wire) to the rheostat from fuse #16 for power to the gauge itself. I have prepared detailed instructions for installation in a Volvo 240 and would be happy to email them to anyone interested.