[DeTomaso] Headlamp Doors Don't Close

[SOBill at aol.com]

Ed,
 
At
>>>>>http://www.panteraplace.com/Electrical/HEADLAMPS%20AND%20DOORS%20P1.pdf  
you will find a diagram of the headlamp system and at  
>>>>>http://www.panteraplace.com/Electrical/HEADLAMPS%20AND%20DOORS%20P2.pdf  you will find a 
diagram of the sequencing of the limit switches.
 
 
Most likely:
Since the buckets go up and stop, the "open" limit switch is OK.  Since the 
buckets, when up, will not go down, the "closed" limit switch  contacts are 
"open." This could be a bad limit switch or the  switch location could have 
changed.
 
Less likely:
The contact on the headlamp relay which provides a chassis ground  to the 
"closed" limit switch is bad. This will prevent the motor from running so  as to 
close the doors.
 
Both situations can be checked as follows:
1) With the buckets up, pull the Green wire from the "closed" limit  switch.
2) Turn the headlamps off. Measure the resistance of the Green wire  to 
chassis ground. The resistance should be around 0 ohms indicating the  headlamp 
relay contacts are good.
3) Measure the voltage at the Brown wire on the "closed" limit  switch. The 
voltage should be around 12 volts. This indicates the motor is  receiving power.
4) Pull the Brown wire(s) from the limit switch and connect them to  the 
Green wire. If the doors start to close, disconnect the  wires. This test proves 
"closed" limit switch contacts lack  continuity when the doors are open.
 
The "closed" limit should have continuity between it's contacts at  all times 
except when the doors are closed. When the doors are closed the  door 
position cam pushes the limit switch plunger in to disconnect the  switch contacts. 
These switches are *probably* repairable. If you take the  switch apart, you 
will find it is about as complex as the average  stone.
 
 
This all sounds pretty complicated ..... and I guess it is pretty  
complicated.
 
Hope this helps,
 
 
SOBill Taylor
sobill at aol.com

 
SOBill  Taylor
sobill at aol.com



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