My temperature gauge needle has been acting odd - almost like a loose connection, so I decided to change my temp sensor. My existing sensor (immediately above the knock-sensor) has only one quick-connect lug on it that a clip goes over (see picture in link below).

http://www.volvo-saab.nm.ru/cat/460191.gif

When ordering the new one however, it seems the proper one for my model (1985 740 GLE Non-Turbo Sedan) is Part # 1362645 - a 2-terminal connection (see pic in link below).

http://www.volvo-saab.nm.ru/cat/1362644.gif

It looks like the previous owner changed the sensor and didn't install the correct one. I now have to connect the 2-wire sensor but I only have one wire coming off that harness. Does anyone know whether the other wire going to the sensor is grounded ? If not, where is it going to ?

Thanks !

Noel

The two wire sensor as you show is indeed a gauge sensor, not the FI sensor. I'm not sure of its application in an 85, but I know it is the one used in a 92 940. The single terminal sensor is the gauge sender in all the rest of my cars which are 240s. The element is the same, and my experience is the single terminal senders are very reliable while the second one you show (the one you bought) exhibits exactly the sort of intermittent loose-connection behavior you report.

To use that sensor, you'd have to get the correct plug to fit anyway, then ground the second terminal.

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Art Benstein near Baltimore

Thanks for the info Art. The Scan-Tech site (see below - very useful as it shows Part #s and pictures) is where I picked the pictures up from. It's evident the old sensor is the 240 style as you mentioned. I just wanted to make sure one of those terminals on the new sensor is supposed to be grounded.

http://www.volvo-saab.nm.ru/cat/electrical-sensors.html

By the way - I'm putting together that really neat radiator-pressure gauge you build from an old turbo-gauge. I was actually hoping to put-together a temperature gauge for my tranny (I have a ZFHP22 that I need to make sure is always in good health). Any ideas ?

Noel

Piping that pressure gauge to the expansion tank was awfully convenient and simple compared with adding a temperature sensor to the tranny. Do you even have accessory gauge spots in a 7 series? Does the ZF use the radiator for a cooler? I just barely know what ZF stands for auf Deutsch.

By the way, that pressure gauge didn't help me any the last time (two weeks ago) I blew a gasket. For the gauge to work you have to watch it. A coolant level float would be much better complete with idiot light.
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Art Benstein near Baltimore

Actually if you have a 740 without turbo, you have 2 blank gauge-spots on the enclosed-dash console: one for the Voltmeter and the other for the turbo. Both these gauges come only with a turbo. I picked up a turbo-dash from the yard, and have already transferred the Voltmeter across, so I have a turbo-gauge just begging to be used.

The 700 series radiators have a separate tranny-cooler built into them that is connected to the ZF (and AWxx too I believe) tranny. The link below shows the cut-out tranny-cooler section of this radiator.

Talking about radiators - do you know of a quick way to fix a tiny leak in a copper radiator ? Mine is at the seam of the radiator and top-spout. I know I know.. I should get it fixed properly, but I need to patch it up for a week or two until I am free enought to get it off the car. Does JB Weld work ?

Noel

That brings back a memory. About four years ago I cleaned a spot on a tank seam, as I recall, on the metal rad that came with a 79 I bought at that time. Cleaned it with a wire brush and brushed on acid flux. Then using a mapp gas torch, heated the area carefully until the solder wicked in trying to avoid disturbing the rest of the seam.

The memory is pleasant, noting I haven't needed to think about it since then. That and the red coolant that is still in that car.
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Art Benstein near Baltimore

the two wire is the ECU temp sender. Gauge sensor has only one lug.