cruise control driving me mad

I have just picked up a 1994 transport v6 3.8 and love it, only problem i have is the cruise control not working. i have checked the vacum bellows under the hood. and the brake light switch conection are all good inc the vacum valve on the brake switch. the master on/off accel/set switch is also fine. the rpm counter and speedo are ok so i think the speed sensor is ok. help!!!

Welcome to AF!!

The speed sensor will cause issues so go ahead and change it and see what happens.

Is there any way to test the sensor first as i think parts are going to be hard to sourse in the uk

DO you have the CEL on? Early '94 at least can be flashed easily if the plug www.avigex.ca/xport/plug.jpg has contacts A and B:
www.avigex.ca/xport/readingcodes.jpg
Codes 21,22,
www.avigex.ca/xport/dtc21.jpg and some others will prevent operation of the cruise control. Some of these codes at same time inhibit operation of 4th gear and TCC....this can be checked easily as change from D to OD or from OD to D would not make any difference.

thank you, i have noticed there seems to be no OD, my socket is a little different from the one your pic. could i have a older model it was imported into the uk 1994 by USAF so it may be older it only has three connections

_____________
| o o o o o o |
| o o o o o o |
-------------- these are the connections

NO: obviously this is an advanced '94 model: it is the next version of the diagnostic system, not OBD2 but something in between ..... and this one requires a code reader: it cannot be flashed.
ANyway, what you say suggests your CEL must be on. Anyway, if not done already, try to clean the memory as described above but I would certainly test the throttle position sensor: reading between the center pin and one end must read a continousy variable resistor value betwen 0 and full throttle, something like from 200 ohms to 7000 ohms..the upper value may be more or less, what is important is a steady change of value without misses or jumps as you depress throttle. This is a common issue and replacement of the throttle position sensor is not a big deal...although the screws require some fancy jiggling onless you completely remove the throttle body...but it can be done.
www.avigex.ca/xport/MAFArea.jpg
www.avigex.ca/xport/maf.jpg
www.avigex.ca/xport/maflocation.jpg
www.avigex.ca/xport/tpsloc.jpg
dtc21 /dtc22 are OBD1 ..they have a 5 digit alphanumeric like P0123 equivalent in obd2

Sorry for being english but wtf is CEL

Check Engine Light. Sorry I hate acronyms too...but get used to....

OK i have checked the TP sensor and this seems to be US i have 5v(grey) -(black) but no output on the sensor (dark blue) i think this sensor is same as sadaam. although the car runs fine would this upset the cruise system. i am just leaving to go home for the night so will check the OD and check back when i get home, by the way i also fixed my dodgy wipers thanks to the forums

.. i have 5v(grey) -(black) but no output on the sensor (dark blue)..would this upset the cruise system.

OK....I just question if you checked on sensor side or plug side, or if you checked the unit as connected and read the voltages from the wires by piercing through with a needle...which is what I do sometimes. Checking voltages must be done connected with key ON, while the resistance test can be done disconnected....anyway the probability of TPS failure is high and I do not know your technical background but I figure out you can do it.

Was that Cehck engine light ON?.... And yes as described in dtc21, this disables the cruise control. ANd I.m glad you found the tread about the wipers.

Yes the sevice engine soon lamp is on all the time. i checked the wiring harness and the sensor wiring is ok sensor is bad. are these sensors easy to get in the states, i think i will have to prder one from there no chance in the uk

CHechk at www.rockauto.com this at least gives an idea of price.
CHeck also ebay....will take a look too.
http://cgi.ebay.com/ebaymotors/Throttle-Position-Sensor-TH113-Buick-Chevy-Olds_W0QQcmdZViewItemQQcategoryZ33557QQihZ019QQite mZ8049368691QQrdZ1QQsspagenameZWD1V#ebayphotohosti ng
http://cgi.ebay.com/ebaymotors/THROTTLE-POSITION-SENSOR-FOR-GM-P-N-TH113_W0QQcmdZViewItemQQcategoryZ33558QQihZ010QQit emZ200028213156QQrdZ1QQsspagenameZWD1V

these 2 are exact match.

WOW i have some how found a 1994 transport in a breakers yard in the north of england that have the parts i need i will post again when i recieve and fit them thanks for all your help

UPDATE changed the tps reset the cel light and (*)(*) cruise and OD both work fine, You now you transports